Both assays rest on the same biological foundation: the cell-mediated immune response that T lymphocytes mount against specific Mycobacterium tuberculosis antigens. When sensitized T cells encounter peptides from the TB-specific proteins ESAT-6 and CFP-10, they release interferon-gamma, a signaling molecule whose presence reveals antigen-specific immune memory. QuantiFERON-TB Gold Plus, manufactured by Qiagen, incubates whole venous blood overnight with these antigens and then measures the accumulated IFNγ using an enzyme-linked immunosorbent assay, or ELISA. T-SPOT.TB, from Oxford Immunotec, takes a different route: it first isolates peripheral blood mononuclear cells from the blood, standardizes their number, and then counts the individual IFNγ-secreting T cells with an enzyme-linked immunospot assay, known as ELISPOT. QuantiFERON additionally includes peptides recognized by TB-specific CD8+ T lymphocytes, broadening the immune cell populations it stimulates beyond the CD4+ compartment.

The study, conducted at the Ramus laboratory between January 1 and December 31, 2024, processed a total of 7,392 patient samples: 6,887 with QuantiFERON-TB Gold Plus and 505 with T-SPOT.TB. The outcome distributions differed markedly between the two platforms. QuantiFERON yielded negative results in an expected 92.3 percent of samples and positive results in only 5.3 percent, reflecting the low TB prevalence in Bulgaria, a high-income country with established tuberculosis control programs. T-SPOT.TB, by contrast, produced 59.8 percent negative and 24.6 percent positive results, a substantially higher positivity rate that hints at its greater analytical sensitivity in populations with low T-cell counts, such as immunosuppressed patients.

Perhaps the most striking differences emerged in the gray zones of testing. Borderline and indeterminate results, the categories that most frustrate clinicians, hovered around 2 percent for QuantiFERON but reached 5.7 percent and 9.5 percent, respectively, for T-SPOT.TB. The indeterminate rate for T-SPOT.TB dropped to 5.3 percent when 21 patients on biological therapy were followed up and their results subsequently converted to negative. QuantiFERON recorded indeterminate results in only 0.4 percent of cases overall, rising to 1.4 percent among patients receiving biological therapy, while 0.5 percent of its results were classified as borderline and 0.1 percent produced no valid outcome. T-SPOT.TB, meanwhile, classified 5.7 percent of results as borderline and failed to generate a valid result in 0.4 percent of tests.

To probe the clinical meaning of these differences, the researchers analyzed 94 patients who underwent both tests, either simultaneously or within defined intervals of up to one year, along with 12 patients who were tested multiple times with a single method. The dual-tested cohort had a mean age of 52 years, ranging from 21 to 85, and comprised 44 females and 50 males. Concordance between the two assays appeared in 51 individuals, or 54.3 percent: 31 had concordant positive results, 17 had concordant negative results, and 3 showed indeterminate results in both tests. Discrepancies surfaced in the remaining 43 patients, or 45.7 percent, a proportion that demands careful clinical interpretation.

The analysis of these discordant cases revealed a reassuring pattern. In 61 percent of the discrepancies, or 26 of 43 patients, results shifted from indeterminate or borderline to negative, or the reverse, within one to six months, a degree of variability the authors deem acceptable under existing guidelines. Among the 17 individuals, or 39 percent, whose results changed from positive to negative or indeterminate, further investigation showed that all had initiated biological therapy. This finding carries significant weight: immunosuppressive treatments can suppress the T-cell response that both assays measure, converting a previously detectable antigen-specific reaction into an undetectable one. Among the 12 patients repeatedly tested with T-SPOT.TB over intervals of four to eight months, three showed consistent positive results, two showed consistent negative results, and seven experienced changes, all of whom were on biological therapy.

Statistical analysis quantified the agreement between the two platforms. Cohen’s kappa, a measure of inter-rater reliability, came in at 0.312, indicating significant but fair agreement, far from the perfect concordance of 1. However, when indeterminate and borderline results were omitted from the calculation, the agreement became substantial, with a kappa of 0.697, much closer to perfect. Under this refined analysis, 85.7 percent of samples were concordant while 14.3 percent were discordant. Sensitivity and specificity also diverged depending on which test served as the reference: T-SPOT.TB, compared to QuantiFERON, showed a sensitivity of 83.78 percent and a specificity of 89.47 percent, while QuantiFERON, compared to T-SPOT.TB, demonstrated a sensitivity of 93.94 percent and a specificity of 73.91 percent.

Each assay carries distinct methodological advantages that shape its clinical niche. T-SPOT.TB, as an ELISPOT-based assay, standardizes the number of peripheral blood mononuclear cells, which may provide greater sensitivity in immunocompromised patients or those with lymphopenia, since it reduces the impact of low cell counts on the result. QuantiFERON, as a whole-blood ELISA-based assay, is technically simpler, less labor-intensive, and more easily standardized, making it better suited for high-throughput laboratory settings. Its inclusion of antigen tubes designed to stimulate both CD4+ and CD8+ T-cell responses may offer advantages in certain clinical contexts. The choice between them, the authors suggest, should depend on patient characteristics, laboratory capacity, and clinical indication rather than on any universal superiority of one platform.

The study also spotlighted a compelling clinical case: a 55-year-old man with a persistent subfebrile condition and swelling in the area of one testicle, who consulted a urologist and underwent periodic antibiotic therapy with isoniazid without lasting effect. Roughly a decade earlier, he had tested positive by QuantiFERON. When retested twice within about a month, both QuantiFERON and T-SPOT.TB returned positive results, pointing to extrapulmonary tuberculosis after a pulmonary form of the disease was ruled out. Six months of specific anti-TB therapy produced a lasting effect on his clinical symptoms, and he has remained stable since, with no chills, fatigue, or fever. A specialist in extrapulmonary tuberculosis indicated that the test may remain positive for a prolonged period, illustrating how IGRA positivity can persist even after successful treatment.

The broader context reinforces the value of these findings. A health technology assessment by Ontario Health, encompassing 12 systematic reviews and more than 500 primary studies, demonstrated that IGRAs serve as effective rule-in tests for latent tuberculosis infection due to consistently high specificity, outperforming the tuberculin skin test in reducing false positives, particularly among immunocompromised populations, children, elderly individuals, and BCG-vaccinated persons. Economic analyses from five Canadian studies revealed that IGRA testing proved cost-effective or cost-saving for high-risk latent TB populations, with healthcare providers expressing strong preference for the single-visit requirement compared to the multiple visits demanded by skin testing. Yet the ability of IGRAs to yield indeterminate results in immunocompromised patients signals the need for further clinical investigation when skin tests may produce false negatives.

Both assays share inherent limitations. Neither can reliably differentiate between latent TB infection and active TB disease, and both depend on a robust host immune response, meaning false negatives may occur in immunocompromised individuals, young children, or patients with advanced disease. A recent systematic review and meta-analysis of IGRAs in people living with HIV, covering 6,525 patients from 45 studies, found that while both tests demonstrated acceptable specificity, their sensitivity was lower, particularly for latent TB infection, suggesting IGRAs may be more reliable for detecting active TB than for ruling out latent infection in immunocompromised populations. The variation in antigen-specific T-cell responses observed in the current cohort may also reflect differences in exposure history, BCG vaccination status, or concurrent infections.

From a clinical perspective, discrepancies between QuantiFERON and T-SPOT.TB results necessitate careful interpretation in conjunction with epidemiological risk factors, radiological findings, and clinical presentation. For borderline or discordant cases, repeating the IGRA or performing both tests sequentially may improve diagnostic confidence, particularly in high-risk groups. The retrospective nature of the study and the lack of detailed clinical data on individual disease activity, concomitant medications, and duration of biological therapy represent limitations that future prospective designs should address through detailed patient stratification and combined analysis of qualitative and quantitative results.

The bottom line for clinicians is clear: the results from both IFNγ-based tests are comparable, with acceptable variation over time, and either method can be relied upon in routine laboratory diagnostics. However, significant changes in results, whether a sharp conversion from positive to negative or the emergence of indeterminate readings, should always be interpreted in light of ongoing specific or biological therapy. As tuberculosis control efforts intensify worldwide and biological therapies continue to expand across medicine, this real-world evidence offers laboratories and physicians a practical roadmap for navigating the nuances of interferon-gamma testing in the patients who need it most.

Subject of Research: Comparative diagnostic performance of two interferon-gamma release assays for Mycobacterium tuberculosis infection

Article Title: Comparative results of two IGRA tests for determining the specific response against Mycobacterium tuberculosis infection

Article References: Stoilov, P., Mihova, A., Mihaylov, R., Zlateva, S., Dimcheva, P., Pentchev, E., Kalcheva, M., Pencheva, B., Naseva, E., & Velikova, T. (2026). Comparative results of two IGRA tests for determining the specific response against Mycobacterium tuberculosis infection. Pharmacia, 73, Article e167649. https://doi.org/10.3897/pharmacia.73.e167649

Image Credits: AI Generated

DOI: 10.3897/pharmacia.73.e167649

Keywords: tuberculosis, IGRA, QuantiFERON, T-SPOT.TB, interferon-gamma, diagnostics, latent TB infection, biological therapy, Comparative, results, tests, determining

Natural killer cells are innate immune lymphocytes that patrol the bloodstream and tissues, eliminating virus-infected and malignant cells without the antigen-specific training that T cells require. Their cytotoxicity is governed by a balance of activating and inhibitory receptors, and when they encounter a target cell they can deploy perforin and granzymes to trigger apoptosis. Beyond direct killing, NK cells are prolific producers of interferon-gamma, a cytokine that shapes both innate and adaptive immune responses. This dual capacity — cytotoxicity and cytokine output — is what makes them attractive candidates for adoptive cell therapy in solid tumors like breast cancer.

But translating that promise into a clinical product requires large numbers of functional cells, and that is where the difficulty lies. Autologous NK cells must be isolated from a patient’s peripheral blood mononuclear cells and expanded ex vivo under cytokine-driven culture conditions to reach therapeutic doses. The expansion capacity of these cells varies enormously from one individual to another, and clinicians have had few reliable ways to gauge that potential in advance. Age, circulating leukocyte counts, the frequency of NK cells in peripheral blood, and the initial number of NK cells available for culture have all been examined as possible predictors, but none has proven consistently informative.

The research team, led by Dai Khac Do and including Trang Thi Vu, Hai The Phung, Kien Trung Hoang, Tuan Ngoc Nguyen, Dung Dang Nguyen, Hai Anh Vu, and Thuc Cong Luong, approached the problem with a deceptively simple assay. They drew peripheral blood from 33 patients with breast cancer and subjected whole-blood samples to a standardized interferon-gamma release assay. This test measures how much IFN-γ circulating immune cells — NK cells chief among them — release when stimulated, providing a functional readout of NK cell activity rather than a mere count of cells present. The assay requires no complex cell isolation and can be performed on whole blood, making it potentially suitable for routine clinical laboratories.

After establishing each patient’s baseline NK cell activity, the researchers isolated peripheral blood mononuclear cells and expanded the NK cells ex vivo under cytokine-based culture conditions. Once the expansion period concluded, they compared the laboratory-measured growth against the pre-treatment IFN-γ signal. The result was striking: baseline NK cell activity showed a significant positive correlation with expansion capacity, with a Spearman rank correlation coefficient of 0.46 and a p-value of 0.007. In plain terms, patients whose blood produced a stronger IFN-γ response at the outset tended to have NK cells that multiplied more vigorously in culture.

Just as telling was what did not predict expansion. Age, total leukocyte counts, the proportion of NK cells within the peripheral blood lymphocyte pool, and the absolute number of NK cells available at the start of culture showed no significant association with how well the cells expanded. This is a crucial distinction for the field. It suggests that the functional fitness of NK cells — their readiness to respond and produce cytokines — matters more than how many are present. A patient could have a robust circulating NK cell population yet still yield cells that expand poorly, while another with a modest frequency might harbor cells with superior proliferative potential once stimulated.

The implications reach beyond breast cancer. Adoptive NK cell therapy is being explored across a range of malignancies, and the inter-individual variability in expansion has been a recurring frustration for clinicians and manufacturers alike. A biomarker that can be measured from a simple blood draw before any culture begins would allow treatment teams to stratify patients, set realistic expectations for cell yield, and potentially adjust culture strategies or choose alternative cell sources — such as allogeneic or cell-line-derived NK products — for those whose autologous cells are unlikely to reach therapeutic numbers.

The study’s authors are careful to frame their finding as a candidate biomarker rather than a validated clinical tool. The cohort of 33 patients is modest, and the correlation, while statistically significant, explains only a portion of the variability in expansion outcomes. Larger studies across diverse patient populations and cancer types will be needed to confirm the relationship and to determine whether the IFN-γ signal can reliably guide treatment decisions. The researchers also note that the assay’s standardization — the precise stimulation conditions and measurement protocol — will require refinement before it can be deployed as a routine pre-treatment screen.

Still, the conceptual advance is significant. For the first time, a functional, cytokine-based readout from whole blood has been linked to the ex vivo expansion potential of a patient’s own NK cells in a solid tumor setting. The finding moves the field away from a purely quantitative view of cell availability toward a qualitative assessment of cell fitness. If validated, the IFN-γ release assay could become a standard pre-treatment evaluation, helping clinicians decide which patients are best suited for autologous NK cell therapy and which might benefit from alternative strategies.

The research, published in BMC Cancer, was conducted with ethics approval from Vietnam Military Medical University and the National Cancer Hospital, and all participants provided written informed consent. The study received no external funding, and the authors declare no competing interests. As NK cell-based immunotherapy continues to advance toward broader clinical application, this work offers a practical step toward personalized cell therapy — one that begins not in the culture flask, but with a single measurement from a tube of blood.

Subject of Research: Immunology

Article Title: Baseline IFN-γ-based natural killer cell activity is associated with ex vivo expansion capacity of autologous NK cells in patients with breast cancer

Article References: Vu, T. T., Phung, H. T., Hoang, K. T., Nguyen, T. N., Nguyen, D. D., Vu, H. A., Luong, T. C., & Do, D. K. (2026). Baseline IFN-γ-based natural killer cell activity is associated with ex vivo expansion capacity of autologous NK cells in patients with breast cancer. BMC Cancer. https://doi.org/10.1186/s12885-026-16978-0

Image Credits: AI Generated

DOI: 10.1186/s12885-026-16978-0

Keywords: natural killer cells, breast cancer, immunotherapy, interferon-gamma, biomarker, cell therapy, Baseline, IFN-, based, natural, killer, cell

The research, led by Yu Shen and Haibo Shen of the Department of Urology at Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, together with colleagues at Shanghai Jing’an District Central Hospital and the Shanghai Institute of Immunology, set out to resolve a longstanding puzzle. GSDMB is known to be highly expressed in bladder cancer, and previous work had implicated the gasdermin family in anti-tumor immunity, but the precise functional role of GSDMB in shaping the response to immune checkpoint inhibitors had remained unclear. The new study provides what the authors describe as a novel mechanism linking a tumor-intrinsic signaling pathway to the recruitment and activation of cytotoxic immune cells within the tumor microenvironment.

At the heart of the discovery is a signaling axis that the researchers designate as GSDMB–DDX5–Sema7a–CD8+ T cell. According to the study, when GSDMB is overexpressed in bladder cancer cells, it does something unexpected for a protein of its class: it translocates to the nucleus. Once inside the nucleus, GSDMB physically interacts with DEAD-box helicase 5, or DDX5, a well-characterized RNA helicase that participates in the regulation of transcription. Through this interaction, the GSDMB–DDX5 complex upregulates the expression of Semaphorin 7A, or Sema7a, a secreted signaling molecule that the study identifies as the critical downstream effector of the pathway.

Sema7a, once produced by the tumor cells, is secreted into the surrounding tumor microenvironment, where it performs a crucial recruiting function. The researchers demonstrate that secreted Sema7a facilitates the infiltration of CD8+ T cells into the tumor. These cytotoxic T lymphocytes are the principal assassins of the adaptive immune system, capable of recognizing and killing tumor cells directly, and their presence within a tumor, rather than merely around its margins, is one of the strongest predictors of response to immunotherapy. Tumors that are densely infiltrated by CD8+ T cells are often described as immunologically hot, whereas tumors that exclude these cells tend to resist checkpoint inhibitors regardless of how many T cells circulate in the bloodstream.

The study goes further than simply counting infiltrating cells. The researchers found that the CD8+ T cells recruited into GSDMB-expressing tumors were not only more numerous but also more functionally potent. Tumor-infiltrating CD8+ T cells in this setting showed enhanced expression of three hallmark mediators of cytotoxic anti-tumor activity: interferon-gamma, tumor necrosis factor-alpha, and granzyme B. Interferon-gamma and tumor necrosis factor-alpha are inflammatory cytokines that coordinate and amplify immune attacks on tumors, while granzyme B is a serine protease that T cells deliver into target cells to trigger their death. The coordinated elevation of all three molecules indicates that the recruited T cells arrive in an activated, tumor-killing state rather than in an exhausted or suppressed condition.

This mechanism has direct consequences for anti-PD-1 therapy. Immune checkpoint inhibitors such as anti-PD-1 antibodies work by releasing the molecular brakes that tumors place on T cells, but they can only succeed if tumor-reactive T cells are present in the tumor microenvironment in the first place. By promoting the infiltration and activation of CD8+ T cells, GSDMB effectively increases the supply of targetable immune cells, allowing anti-PD-1 treatment to operate on a larger and more vigorous T cell population. The authors report that GSDMB synergizes with the efficacy of immune checkpoint inhibitor therapy in bladder cancer through this promotion of CD8+ T cell infiltration and effector function, establishing the protein as a genuine partner to checkpoint blockade rather than an incidental correlate.

The mechanistic findings are notable because they assign a transcriptional regulatory role to GSDMB, a member of the gasdermin family whose members are classically associated with pyroptosis, a form of inflammatory programmed cell death. The demonstration that GSDMB can move into the nucleus and, through its interaction with the helicase DDX5, drive the transcription of Sema7a expands the known functional repertoire of this protein family. It also reframes gasdermin biology in the context of cancer immunology: rather than acting solely as an executor of cell death, GSDMB in bladder cancer appears to function as a tumor-intrinsic organizer of the immune microenvironment, shaping which immune cells enter the tumor and how aggressively they behave once inside.

Beyond its mechanistic interest, the study carries practical implications for patient care. The authors conclude that GSDMB may serve as a potential prognostic biomarker for outcomes in patients with bladder cancer treated with anti-PD-1 therapy. If validated in larger clinical cohorts, a GSDMB-based test could help oncologists identify, before treatment begins, which patients are likely to respond to checkpoint inhibitors and which might be better served by alternative or combination strategies. This kind of predictive stratification is a pressing unmet need in bladder cancer, where anti-PD-1 agents are used in both metastatic settings and in certain non-muscle-invasive disease contexts, yet response rates vary widely between individuals.

The research also suggests potential therapeutic avenues that extend beyond biomarker development. If the GSDMB–DDX5–Sema7a pathway can be pharmacologically enhanced in tumors with low endogenous GSDMB activity, or if Sema7a itself can be delivered or mimicked to draw CD8+ T cells into immunologically cold tumors, clinicians might one day convert non-responsive bladder cancers into responsive ones. Conversely, the pathway offers a mechanistic explanation for resistance that could be targeted diagnostically: patients whose tumors lack GSDMB expression, and therefore lack the Sema7a-driven recruitment signal, might be candidates for therapies that recruit immune cells through alternative routes, such as oncolytic viruses, cancer vaccines, or chemokine-modulating agents.

The study was conducted with oversight from the Institutional Animal Care and Use Committee of Xinhua Hospital and the hospital’s Ethics Committee, with informed consent obtained from all human participants, and it was supported by grants from the Shanghai Jing’an District Health Commission and the Cross-disciplinary Fund of Xinhua Hospital. Published as an open-access article, the work adds bladder cancer to the growing list of malignancies in which tumor-intrinsic molecular programs are being mapped onto the architecture of the immune microenvironment. As the field of immuno-oncology moves from broad checkpoint blockade toward rational, mechanism-guided combination therapy, findings such as the GSDMB–DDX5–Sema7a axis illustrate how a single tumor protein can orchestrate an entire chain of immune events, from gene transcription in the cancer cell nucleus to the arrival of armed cytotoxic T cells at the tumor front, and how understanding that chain may ultimately determine whether a patient’s immune system can be mobilized to fight back.

Subject of Research: The role of GSDMB in enhancing anti-PD-1 immunotherapy response through Sema7a-mediated CD8+ T cell infiltration in bladder cancer

Article Title: GSDMB synergizes anti-PD-1 efficacy via Sema7a-mediated CD8+ T Cell infiltration in bladder cancer

Article References: Shen, Y., Zhang, S., Yu, S., Chen, K., Li, J., Chen, Z., Ren, T., Liu, H., Xu, D., Wang, Y., & Shen, H. (2026). GSDMB synergizes anti-PD-1 efficacy via Sema7a-mediated CD8+ T Cell infiltration in bladder cancer. Cancer Immunology, Immunotherapy. https://doi.org/10.1007/s00262-026-04597-4

Image Credits: AI Generated

DOI: 10.1007/s00262-026-04597-4

Keywords: bladder cancer, GSDMB, Sema7a, DDX5, CD8+ T cells, anti-PD-1, immune checkpoint inhibitors, immunotherapy, tumor microenvironment, biomarker, granzyme B, interferon-gamma

The study, led by Senior Research Scientist James Godwin, focused on fingertip regeneration in mice, a rare example of a mammalian tissue that can partially regrow after amputation. Like humans, mice can regenerate multiple tissue types at the tips of their digits, including bone, skin, and nail, but only up to a certain point. This limited regenerative capacity has long made the digit tip a valuable model for understanding why mammalian repair falls short of the spectacular regeneration seen in animals like salamanders. Godwin, who is also an assistant professor at the MDI Biological Laboratory in Bar Harbor, Maine, built the project on his earlier discoveries that macrophages—innate immune cells—are essential for heart regeneration in axolotls, salamanders famous for regrowing entire lost limbs.

“There’s always been a bit of an underappreciation of how important the immune system is in directing these repair processes, but there is a lot of accumulating evidence that this is what really determines the success or failure of most wounds,” Godwin said. His team set out to examine the role of adaptive immune cells, the branch of the immune system that learns to recognize specific threats such as viruses and cancer cells. What they found was a system of checks and balances in which the same cellular family both hinders and protects regeneration, depending on which members are present and what signals they produce.

The experimental design was unusually broad. The researchers worked with 16 genetically diverse strains of mice, including some engineered to lack different types of immune cells. This diversity mattered because immune behavior varies across genetic backgrounds, and the team wanted conclusions that would not depend on the quirks of a single laboratory strain. Across the panel, a clear pattern emerged: when adaptive immune cells were absent, regeneration of the injured digit tip was faster and more effective. The immune system, in other words, was not a passive bystander in repair—it was an active brake on the process.

Zooming in, the researchers identified CD4+ T cells as the chief culprits. These cells, sometimes called “helper” T cells because they coordinate immune responses, strongly inhibited regeneration. Further experiments revealed something more aggressive than mere interference: the CD4+ T cells could directly kill progenitor cells, the immature cells that give rise to the specialized cells needed to rebuild bone. Under the microscope, imaging showed CD4+ T cells attacking progenitor cells, which died as the regeneration process stalled. The team pinpointed an immune signaling molecule called interferon-gamma as a major driver of this cytotoxic activity. When CD4+ T cells were unable to produce interferon-gamma, they no longer blocked regeneration, linking the destructive behavior to a specific molecular pathway.

“CD4+ T cells are negative forces in this context, but they’re also the guardians of our body in terms of cancer and viruses,” Godwin explained. “It’s possible that because our human body has evolved to balance the ability to repair and the ability to ward off these threats, that we’ve landed in this situation where we don’t have a lot of regenerative capacity, but we have good cancer and viral surveillance.” The idea reframes the limited regenerative power of mammals not as a simple evolutionary failure but as the price of a vigilant immune system. A body that tolerates rapid, progenitor-driven growth everywhere might also tolerate tumors; a body that ruthlessly surveys its tissues for abnormal cells may inevitably attack the benign growth needed for regeneration.

Yet the story does not end with destruction. Not all CD4+ T cells behaved the same way. Regulatory T cells, a subset known as Tregs that normally keeps immune responses under control, turned out to be protectors rather than attackers. These cells shielded the progenitor cells involved in rebuilding the fingertip from assault by other CD4+ T cells. When the researchers removed Tregs from the equation, regeneration was delayed, and the immune system began damaging even uninjured bone—a sign that the protective subset restrains not only the attack on rebuilding tissue but also collateral damage to healthy structures nearby.

The therapeutic implications of that protection became clear in the team’s rescue experiments. Adding Tregs back restored regeneration, as did increasing levels of RANKL, a naturally occurring molecule that helps control bone breakdown and remodeling. RANKL is well known to bone biologists as a key regulator of osteoclasts, the cells that dismantle bone, but its role here suggests it also participates in the immune dialogue that permits reconstruction. Together, the findings offer new insight into how the immune system interacts with bone and how that balance may be disrupted by disease and aging, Godwin noted—conditions in which Treg function and bone remodeling are both known to change.

More work is needed to determine whether similar mechanisms operate in human tissue, but the study already points toward practical strategies. Cell-based therapies for severe injuries—transplants of stem cells or progenitor cells intended to rebuild damaged spinal cords, bones, or other structures—often struggle because the transplanted cells fail to survive in their new environment. If destructive immune responses are part of the reason, then protecting transplanted cells from attack could complement current efforts to deliver or activate them. The regenerative medicine field has concentrated heavily on sourcing the right cells; this research suggests an equally important question is how to keep those cells alive once the immune system notices them.

“In the future, if somebody had an injured spinal cord or major damage to one of their bones, we might be able to use targeted immunotherapy to temporarily shift the immune system and ramp up the cells that support regeneration while suppressing those that interfere with it,” Godwin said. He was quick to caution that no therapy is ready and no patients are on the horizon yet, but identifying what needs to change is an essential step toward getting there. The study’s central lesson—that regeneration is not capped by an immutable biological limit but shaped by a negotiable immune balance—offers a reason for optimism. What once looked like a hard ceiling on mammalian repair may instead be a dial, waiting for the right combination of immune signals to turn it.

Subject of Research: The dual role of T cells in mouse digit-tip regeneration

Article Title: ‘A balancing act:’ The same immune cells hinder and protect tissue regeneration

Article References: ‘A balancing act:’ The same immune cells hinder and protect tissue regeneration. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: tissue regeneration, T cells, regulatory T cells, immunology, digit tip regeneration, interferon-gamma, RANKL, progenitor cells, regenerative medicine, Jackson Laboratory, balancing, same

The assembloid model, built upon a foundational shaking organoid co-culture approach, integrates patient-derived colorectal cancer organoids, autologous cancer-associated fibroblasts, and allogeneic peripheral blood mononuclear cells within a collagen matrix. Using a hydrogel-in-oil emulsion system, the researchers generated compact spherical structures where all three cell types are spatially organized to mimic the cellular heterogeneity and architecture of the native tumor microenvironment. Whole-mount multiplex imaging and immunohistological analysis confirmed successful co-engraftment, revealing large E-cadherin-positive epithelial cancer organoid structures embedded within a dense network of Vimentin-positive fibroblasts. Importantly, while CD8-positive and CD4-positive T lymphocytes and CD68-positive macrophages successfully infiltrated tumor-dense areas, the majority of immune cells preferentially localized within stroma-rich regions, reflecting the structural complexity found in real tumors.

Before deploying the platform for drug evaluation, the team performed a careful scaling analysis to determine the optimal balance between tissue complexity and metabolic stability. By proportionally scaling both construct volume and absolute cell number, doubling the input for 10 microliter droplets and quadrupling it for 20 microliter droplets, they observed significant size-dependent effects on tissue health. While larger assembloids successfully increased total tissue mass, the expanded physical dimensions resulted in prominent necrotic cores and morphological shifts in the fibroblast compartment, likely due to diffusion-limited oxygen and nutrient gradients. The researchers therefore selected the baseline 5 microliter architecture, which is sufficient to capture translatable features of tumor hypoxia while preserving optimal cellular health and morphology for evaluating specific stromal-immune responses.

Single-cell RNA sequencing on the assembloids identified distinct cell clusters corresponding to all input populations. The researchers successfully detected colorectal cancer cells robustly expressing epithelial markers such as EPCAM, KRT8, and KRT19, fibroblasts defined by mesenchymal and cancer-associated fibroblast genes including COL1A1, COL3A1, and FAP, alongside a highly diverse immune compartment encompassing CD4-positive T cells, CD8-positive T cells, B cells, plasma cells, natural killer cells, macrophages, and conventional dendritic cells. Assessment across multiple untreated patient-derived lines demonstrated the model’s ability to capture inherent inter-patient heterogeneity within both the immune and stromal compartments, a critical feature for a platform intended to evaluate personalized therapeutic responses.

With the baseline multicellular complexity established, the team evaluated the assembloids’ capacity to respond to interferon-gamma, a master regulator of cell-mediated immunity known for its potential to orchestrate anti-tumor responses and remodel the tumor stroma. Histological assessment via hematoxylin and eosin staining revealed that interferon-gamma treatment resulted in significant growth suppression, evidenced by a marked reduction in overall tissue area. A significant reduction in proliferation was also observed, quantified by the reduced percentage of Ki67-positive tissue area. As expected, a dose-dependent increase in CXCL10 levels was detected in the conditioned media following treatment, with patient-specific differences in secretion highlighting variability in how different patient-derived assembloids respond to the cytokine.

To investigate the functional relevance of CXCL10 secretion, the researchers designed a transwell migration assay placing two assembloids generated from the same patient material in the lower chamber with or without treatment, and CMFDA-labeled naive CD8-positive T cells in the upper compartment. Analysis confirmed that conditioned media from interferon-gamma-treated assembloids significantly enhanced CD8-positive T-cell migration compared to untreated controls. Broader multiplex cytokine profiling confirmed the transition to a highly inflamed microenvironment, characterized by significant elevations in pro-inflammatory cytokines including IL-1α, TNFα, IL-12, and CCL2. Immunohistochemical analysis further confirmed that interferon-gamma treatment potently drove widespread upregulation of both MHC class I and the immune checkpoint molecule PD-L1, predominantly in stromal regions, capturing the cytokine’s paradoxical dual role as both a driver of anti-tumor immunity and a trigger of adaptive immune resistance.

Single-cell transcriptomics then revealed the cell-type-specific mechanics of interferon-gamma signaling. Expression analysis confirmed broad expression of the interferon-gamma receptors IFNgR1 and IFNgR2 across the assembloid compartments, with the highest enrichment in macrophages, fibroblasts, dendritic cells, and colorectal cancer cells. Upon treatment, these clusters exhibited robust upregulation of key T-cell attracting chemokines, namely CXCL9, CXCL10, and CXCL11, with fibroblasts and macrophages showing the most prominent induction. In parallel, interferon-gamma stimulation strongly induced expression of critical immune checkpoint and immunomodulatory molecules, including CD274 (PD-L1) and IDO1, primarily within the macrophage, fibroblast, dendritic cell, and colorectal cancer cell populations, indicating a prominent role for the stroma in mediating immune suppression. Quantification of both pro- and anti-tumor transcriptomic changes identified fibroblasts as the most highly responsive cell population, followed closely by macrophages, dendritic cells, and colorectal cancer cells.

Perhaps the most striking finding emerged from analysis of the stromal compartment. Module scoring demonstrated that interferon-gamma exposure drives a distinct phenotypic transition within the fibroblast population, shifting away from a classical myofibroblast baseline state toward an antigen-presenting cancer-associated fibroblast state. This transition was characterized by robust upregulation of MHC class II molecules such as HLA-DRA, HLA-DRB1, and CD74, alongside key transcription factors including IRF1, STAT1, and CIITA, and immune-modulatory genes such as GBP1, IDO1, and ICAM1. Conversely, structural myofibroblast markers like COL1A1 and COL1A2 were downregulated. Multiplex immunofluorescence staining for Vimentin and HLA-DR validated a consistent increase in the proportion of Vimentin-positive HLA-DR-positive antigen-presenting fibroblasts within the total cancer-associated fibroblast population following treatment, confirming the transcriptomic shift at the protein level.

Given that the clinical application of recombinant interferon-gamma has historically been severely limited by peripheral dose-limiting toxicities and the induction of broad immunosuppressive feedback loops, the team designed a novel panel of attenuated, targeted bispecific molecules intended to localize interferon-gamma receptor activation specifically to the tumor stroma. They utilized fibroblast activation protein, a marker predominantly overexpressed on cancer-associated fibroblasts, as a tumor-enriching target. The researchers engineered constructs with varying FAP binders and VHH domains that bind IFNgR1 or IFNgR2, exploring distinct spatial mechanisms of receptor activation: cis activity, where the molecule binds FAP and activates the interferon-gamma receptor on the surface of the same cell, and trans activity, where the molecule anchors to FAP on a fibroblast but bridges across to activate the receptor on a neighboring cell. They also developed an all-in-one construct integrating multiple anti-FAP binders and anti-IFNgR VHHs into a single unified format capable of engaging both targets simultaneously.

Functional evaluation within the 3D assembloids demonstrated that localizing interferon-gamma activity via FAP successfully uncouples beneficial anti-tumor mechanisms from detrimental immunosuppressive feedback loops. While standard recombinant interferon-gamma provoked massive upregulation of both MHC class I and PD-L1, the cis, trans, and all-in-one targeted molecules elicited minimal PD-L1 upregulation. The targeted constructs still successfully induced CXCL10 secretion at attenuated levels, demonstrating therapeutic potential, and transwell migration assays showed a trend toward enhanced CD8-positive T-cell recruitment, though these changes did not achieve statistical significance over untreated controls at the tested dose. Flow cytometric analysis in two-dimensional co-cultures revealed that exposure to the interferon-gamma variants induced dose-dependent upregulation of CD69 on both CD4-positive and CD8-positive T cells, providing evidence of early immune activation alongside chemotactic signaling. Collectively, these findings confirm that patient-derived assembloids provide a robust, physiologically relevant model to assess complex cellular interactions and screen the localized efficacy of novel, next-generation immunotherapies, paving the way for a more refined, human-derived in vitro strategy to accelerate the discovery and optimization of targeted cancer immunotherapies for solid tumors.

Subject of Research: Cancer immunotherapy preclinical modeling using human 3D assembloids

Article Title: Evaluating cytokine-based therapeutics in human 3D in vitro immune-containing assembloids

Article References: Maenhoudt, N., Lütge, M., Obenloch, M., Caironi, A., Kiratzis, M., Jean-Mairet, P., Graziano, S., Fröbel, P., Hüsser, T., Yángüez, E., Antsiferova, M., Filip, A. M., Müller, C., Leclair, S., Gasser, S., Umaña, P., Colombetti, S., Cremasco, F., & Calabro, S. (2026). Evaluating cytokine-based therapeutics in human 3D in vitro immune-containing assembloids. Frontiers in Cell and Developmental Biology, 14, Article 1930651. https://doi.org/10.3389/fcell.2026.1930651

Image Credits: AI Generated

DOI: 10.3389/fcell.2026.1930651

Keywords: assembloids, cancer immunotherapy, colorectal cancer, interferon-gamma, cancer-associated fibroblasts, tumor microenvironment, organoids, targeted cytokines, Evaluating, cytokine-based, therapeutics, human

The clinical burden of HMPV is substantial and often underestimated. The virus accounts for approximately 4 to 13 percent of hospitalizations associated with lower respiratory tract infections in children under five, and it is recognized as the second most common viral cause of pediatric lower respiratory disease after respiratory syncytial virus. Globally, HMPV is estimated to produce nearly 502,000 hospitalizations and around 11,300 deaths annually in young children, placing its overall impact somewhere between that of RSV and influenza. Severe disease also strikes older adults and immunocompromised individuals. Part of the difficulty in developing a vaccine lies in the virus’s own biology: HMPV interferes with antiviral signaling pathways, suppresses interferon production, and impairs immune cell function, which helps explain why natural infection produces weak, short-lived protective immunity and why reinfections are common.

To overcome this, the research team cast a deliberately wide net across the viral proteome. They retrieved sequences of all eight major HMPV proteins from the CAN97-83 lineage: the fusion (F) and attachment (G) glycoproteins on the viral surface, the small hydrophobic (SH) protein, the matrix proteins M2-1 and M2-2, the nucleoprotein (N), the phosphoprotein (P), and the large RNA-dependent RNA polymerase (L). Each protein was screened for predicted antigenicity using the VaxiJen v2.0 server. The nucleoprotein scored highest at 0.5286, followed by the phosphoprotein, the polymerase L (0.4770), fusion F (0.4711), attachment G (0.4710), M2-1 (0.4163), SH (0.3781), and M2-2 (0.3630). Including internal and replication proteins alongside the surface glycoproteins reflects evidence that both classes contribute to humoral and cellular immunity, making a multi-antigen approach potentially more protective than designs targeting surface proteins alone.

From these proteins, the team predicted three classes of immune epitopes. Cytotoxic T lymphocyte (CTL) epitopes, which would be presented on MHC class I molecules to CD8-positive killer T cells, were identified with NetCTL v1.2 and the Immune Epitope Database (IEDB) resources. Helper T lymphocyte (HTL) epitopes, presented on MHC class II to CD4-positive helper cells, were predicted with NetMHCIIpan and IEDB tools using 10 to 15 amino acid peptides. Linear B-cell epitopes, the targets of antibody responses, were predicted with the IEDB B-cell prediction tool. Every candidate peptide then passed through a safety and quality filter: VaxiJen confirmed predicted antigenicity above a threshold of 0.4, AllergenFP excluded potential allergens, ToxinPred screened out toxic peptides using a threshold of 0.9, and the IFNepitope server flagged peptides likely to induce interferon-gamma, a cytokine central to antiviral immunity.

The final vaccine constructs each contain 24 non-overlapping epitopes: eight CTL, eight HTL, and eight B-cell epitopes, one of each type drawn from every analyzed HMPV protein. The epitopes were stitched together with peptide linkers chosen for their conventional roles in multi-epitope design: alanine-alanine-tyrosine (AAY) linkers between CTL epitopes to support proteasomal processing, glycine-proline-glycine-proline-glycine (GPGPG) linkers between HTL epitopes, and lysine-lysine (KK) linkers between B-cell epitopes. The core epitope region spans 315 amino acids. What distinguishes this study from earlier HMPV immunoinformatics work is the addition of the human B-cell activating factor (BAFF, a 285-amino-acid TNF family member) or the proliferation-inducing ligand APRIL (250 amino acids) at the N-terminus of each construct, connected through an EAAAK linker. Both molecules naturally regulate B-cell survival, differentiation, and antibody production, and prior experimental vaccine studies have shown that BAFF and APRIL can enhance germinal-center reactions and antigen-specific antibody responses in animal models.

The physicochemical profiles of the two constructs suggest they could, in principle, be manufactured as recombinant proteins. The BAFF-adjuvanted construct comprises 533 amino acids with a molecular weight of 57.8 kilodaltons, while the APRIL-containing version is 496 amino acids and 53.63 kilodaltons. Both are predicted to be stable, with instability indices of 32.98 and 31.76 respectively, values comfortably below the threshold of 40 that flags instability. High aliphatic indices (80.28 and 81.69) and negative grand average hydropathicity scores (-0.455 and -0.425) indicate thermostability and hydrophilicity, the latter suggesting compatibility with aqueous solubility. Both constructs were predicted to be antigenic (VaxiJen scores of 0.6776 for the BAFF version and 0.7243 for the APRIL version) and non-allergenic and non-toxic by the screening tools. Secondary structure predictions from the GOR4 and PSIPRED servers showed a balanced mix of alpha-helices, beta-strands, and random coils, with coils predominating, a pattern the authors interpret as supporting both structural stability and exposed, accessible epitopes.

To probe how the constructs might engage the innate immune system, the team performed protein-protein molecular docking against two Toll-like receptors. TLR4 was chosen because previous experimental studies have implicated it in innate responses to HMPV, while TLR1 was included as an exploratory target, with the caveat that TLR1 normally functions as a heterodimer with TLR2. Using structures generated with AlphaFold and the HADDOCK docking platform, the analysis placed each vaccine construct along the leucine-rich repeat domain of the receptors, with multiple predicted contacts. In the TLR4 complex, hydrogen bonds were predicted between Gln185 and Gln187 of the construct and Asn622 and Ser623 of TLR4, along with electrostatic, hydrophobic, and salt-bridge contacts involving residues such as Glu30, Pro27, and Asp50 on the vaccine side and Arg154, Lys184, and Arg337 on the receptor. The TLR1 complex similarly showed hydrogen bonding between construct residue Gln178 and receptor residues Asn518 and Ser515. The authors are explicit that docking demonstrates only structural compatibility, not binding affinity, receptor activation, or signaling.

An immune simulation with the C-ImmSim server, run over 100 time steps under a defined human HLA background, painted a theoretically favorable response profile. Following a single modeled immunization, IgM antibodies appeared first and peaked around days 10 to 12, followed by a class-switched response dominated by IgG1. Interferon-gamma showed the strongest cytokine response, peaking near day 4, with a prominent early IL-2 peak, a pattern consistent with a Th1-oriented cellular response relevant to antiviral defense. Simulated B-cell populations rose to roughly 470 to 480 cells per cubic millimeter by day 6, memory B cells accumulated progressively, and the helper T-cell compartment expanded to about 5,500 cells before declining, with memory T-helper cells increasing to approximately 400 to 450. Population coverage analysis using the IEDB tool predicted that the selected HLA-restricted T-cell epitopes would cover 100 percent of individuals in all eight geographic populations examined, from Central Africa to East Asia to Europe and the Americas, though the number of epitope-HLA combinations recognized per person varied by region.

The study’s authors and its framing are careful about the limits of the work, and rightly so. Every result, from antigenicity scores to docking poses to simulated cytokine kinetics, is a computational prediction resting on algorithmic assumptions rather than biological measurement. The predicted non-allergenic and non-toxic profiles do not establish clinical safety, and the incorporation of BAFF and APRIL carries its own cautionary note: excessive or dysregulated signaling through this pathway is associated with persistence of autoreactive B cells and autoimmune disease, so these endogenous molecules should not be assumed safer than conventional adjuvants. The BAFF and APRIL receptors that would actually mediate their effects, BAFF-R, TACI, and BCMA, were not docked and remain targets for future study. The authors call for molecular dynamics simulations, binding free-energy calculations, recombinant expression, in vitro immunological assays, and ultimately in vivo studies of immunogenicity, safety, and protective efficacy. Until those experiments are done, the constructs stand as rigorously prioritized candidates, an early but structurally detailed step toward closing a significant gap in respiratory virus prevention.

Subject of Research: Immunoinformatics-guided design of BAFF- and APRIL-adjuvanted multi-epitope vaccine candidates against human metapneumovirus

Article Title: Immunoinformatics-guided design and in silico evaluation of BAFF- and APRIL-adjuvanted multi-epitope vaccine candidates against human metapneumovirus

Article References: Alahmadi, R. M., Awadalla, M., Al-Rawi, H. Z., Mubarak, A., Ali Eltayb, W., Abdalla, M., Yu, H., & Alosaimi, B. (2026). Immunoinformatics-guided design and in silico evaluation of BAFF- and APRIL-adjuvanted multi-epitope vaccine candidates against human metapneumovirus. Frontiers in Virology, 6, Article 1949694. https://doi.org/10.3389/fviro.2026.1949694

Image Credits: AI Generated

DOI: 10.3389/fviro.2026.1949694

Keywords: human metapneumovirus, immunoinformatics, reverse vaccinology, multi-epitope vaccine, BAFF, APRIL, Toll-like receptors, molecular docking, vaccine design, interferon-gamma, HLA population coverage, immune simulation

The research, a collaboration between teams at Shandong Provincial Hospital Affiliated to Shandong First Medical University in China and Science for Life Laboratory at Uppsala University in Sweden, focused on a signaling axis that has long been implicated in cancer progression but rarely examined through an immunological lens. The FGFR family of receptor tyrosine kinases, comprising FGFR1 through FGFR4, regulates cell proliferation, survival, migration and differentiation. When these receptors are activated by their ligands or altered by genetic changes, they can drive tumor growth and, as mounting evidence suggests, help cancers hide from the immune system. The researchers set out to determine whether silencing this pathway in colorectal cancer could strip away one layer of that camouflage.

The team’s experimental strategy combined laboratory models with large-scale genomic data. In murine colorectal cancer models, they tested FGFR pathway inhibition alone and in combination with antibodies that block PD-1, the checkpoint receptor that exhausted T cells use to disengage from tumor cells. In parallel, they built in vitro co-culture systems in which T cells and tumor cells interact under controlled conditions, allowing them to measure precisely how FGFR3 blockade changes T cell activation. To connect these mechanistic findings to human disease, they performed RNA sequencing and bioinformatic analyses, including an evaluation of The Cancer Genome Atlas (TCGA), one of the largest publicly available collections of tumor transcriptomic and clinical data.

The results point to a coherent immunological mechanism. When the researchers combined FGFR inhibition with PD-1 blockade, they observed a significant reduction in T cell exhaustion, the dysfunctional state that renders tumor-infiltrating lymphocytes unable to kill their targets. Exhausted T cells express inhibitory receptors, lose their cytotoxic potency and secrete diminished amounts of inflammatory mediators. By reversing this state, the combination treatment appeared to reinvigorate the cellular arm of the antitumor immune response. Equally striking was the effect on myeloid cells: the treatment promoted macrophage repolarization toward an antitumor phenotype. Macrophages are notoriously plastic; within tumors they often adopt a pro-tumor, immunosuppressive identity that suppresses T cells and promotes tissue invasion. Shifting them back toward an inflammatory, tumor-fighting state represents a second, complementary lever on the immune microenvironment.

Transcriptomic profiling provided a molecular explanation for these cellular observations. RNA sequencing revealed that combined FGFR inhibition and PD-1 blockade upregulated immune-related pathways and activated immune-stimulatory genes, effectively rewiring the tumor’s gene expression program toward one that recruits and supports immune attack. In the co-culture experiments, the most direct functional readout came from FGFR3-specific monoclonal antibody treatment, which enhanced the release of interferon-gamma following PD-1 blockade. Interferon-gamma is a signature cytokine of activated T cells and natural killer cells, and its production is a hallmark of productive antitumor immunity. The finding that a monoclonal antibody against a single receptor, FGFR3, could boost this cytokine response when paired with checkpoint blockade suggests that the effect is not a diffuse consequence of general growth factor withdrawal but a targeted immunological shift.

The clinical relevance of these findings was reinforced by the TCGA analysis. The researchers found that high FGFR3 expression correlates with worse prognosis in colorectal cancer patients, linking the receptor’s activity to patient outcomes in a large human cohort. This epidemiological signal matters because it suggests that FGFR3 is not merely a passenger in colorectal tumors but a biologically meaningful participant whose expression marks aggressive disease. It also provides a potential biomarker: patients whose tumors express high levels of FGFR3 might be the ones most likely to benefit from a combination strategy that includes FGFR inhibition, an approach that aligns with the broader movement toward biomarker-guided immunotherapy combinations.

The significance of the work lies in the specific problem it addresses. Microsatellite stable colorectal cancer has been described as a cold tumor type, characterized by low mutational burden, sparse T cell infiltration and an immunosuppressive stroma. Checkpoint inhibitors work best when pre-existing antitumor T cells are present but restrained; in MSS colorectal cancer, that substrate is often missing. Strategies to convert cold tumors into hot ones, including oncolytic viruses, radiation, chemotherapy and targeted agents, have produced mixed results. The new study adds FGFR inhibition to this arsenal, and its dual mechanism, reducing T cell exhaustion while repolarizing macrophages, targets two distinct pillars of immune suppression simultaneously. That combination of effects may explain why the pairing with PD-1 blockade produced such pronounced immunological changes in the models.

It is worth placing the findings in the context of existing FGFR-directed therapeutics. Several FGFR inhibitors, mostly small-molecule kinase inhibitors such as erdafitinib and pemigatinib, are already approved for other cancers with FGFR alterations, including urothelial carcinoma and cholangiocarcinoma. The prospect of extending this drug class into colorectal cancer, not as a standalone cytotoxic agent but as an immunomodulatory partner for checkpoint blockade, represents a conceptual repurposing. The Swedish-Chinese team’s use of an FGFR3-specific monoclonal antibody in vitro also highlights an alternative modality: receptor-specific antibodies may offer cleaner target engagement than broad-spectrum kinase inhibitors, potentially limiting the toxicities that have complicated FGFR-targeted therapy, such as hyperphosphatemia and ocular side effects.

As with any preclinical study, important caveats apply. The work was conducted in murine models and in vitro co-culture systems, which, however sophisticated, cannot fully reproduce the complexity of human colorectal tumors, including their heterogeneous microbiomes, stromal architectures and evolutionary histories. The authors themselves frame their findings as providing a rationale for further investigation rather than as proof of clinical efficacy. Translating the combination into patients will require careful dose-finding, attention to the safety of adding FGFR inhibition to immunotherapy, and clinical trials designed to test whether the biomarker signal from TCGA, high FGFR3 expression predicting poor prognosis, also predicts benefit from the combination. The study was approved by the Review Committee of Shandong First Medical University Affiliated Provincial Hospital and conducted in compliance with ARRIVE 2.0 reporting guidelines, and the authors declare no competing interests.

Nevertheless, the study adds an important piece to one of oncology’s most pressing puzzles: how to make immunotherapy work for the patients who currently derive no benefit from it. By demonstrating that FGFR pathway inhibition reduces T cell exhaustion, repolarizes macrophages, upregulates immune-stimulatory genes and enhances interferon-gamma release in the presence of PD-1 blockade, the researchers have articulated a mechanistically grounded rationale for a new combination strategy in MSS colorectal cancer. If subsequent studies in patients confirm what the mouse models and genomic analyses suggest, the FGFR axis, long studied as a driver of tumor growth, may find a second career as a gatekeeper of antitumor immunity, and its inhibition may help open the door that checkpoint inhibitors alone have been unable to unlock for the majority of colorectal cancer patients.

Subject of Research: FGFR pathway inhibition combined with PD-1 blockade to enhance antitumor immunity in microsatellite stable colorectal cancer

Article Title: FGFR pathway inhibition enhances PD-1 blockade and modulates antitumor immunity in colorectal cancer models

Article References: Shang, Z., Jing, C., Liu, J., Zhang, B., Rúbies Bedós, M., Papakyriacou, I., Mao, Y., & Chen, Y. (2026). FGFR pathway inhibition enhances PD-1 blockade and modulates antitumor immunity in colorectal cancer models. BMC Cancer, 26(1), Article 1227. https://doi.org/10.1186/s12885-026-17105-9

Image Credits: AI Generated

DOI: 10.1186/s12885-026-17105-9

Keywords: colorectal cancer, FGFR signaling, PD-1 blockade, immunotherapy, microsatellite stable, T cell exhaustion, macrophage repolarization, interferon-gamma, TCGA, combination therapy, immune checkpoint blockade, tumor microenvironment

The research team, led by Xing Fan, Jiahe Tian, Bo Zhang and senior authors Chao Zhang, Fu-Sheng Wang and Lei Huang of the Fifth Medical Center of Chinese PLA General Hospital and collaborating institutions in Beijing, Wuhan, Nanning and Hefei, focused on CD4+ T cells, the helper arm of adaptive immunity that orchestrates antiviral responses, supports antibody production and recruits other immune cells to sites of infection. While much vaccine research has centered on neutralizing antibodies directed against the viral spike protein, CD4+ T cells recognize a broader repertoire of viral antigens, including proteins such as nucleocapsid and membrane that are collectively termed non-spike targets. These non-spike-specific responses are thought to contribute to viral clearance and to cross-protection against variants whose spike mutations allow antibody escape.

To measure these responses with precision, the investigators used activation-induced marker assays, a flow cytometry-based technique in which peripheral blood mononuclear cells are stimulated with overlapping peptide pools covering spike or non-spike viral proteins. T cells that genuinely recognize the antigen respond within hours by expressing surface markers such as CD69 and CD154, allowing researchers to quantify the frequency of antigen-specific cells and to classify them into functional subsets. In parallel, the team measured cytokine secretion into culture supernatants, providing a readout of the inflammatory and antiviral signaling capacity of the responding cells. The longitudinal design followed participants across four key time points: before vaccination, after vaccination, before Omicron breakthrough infection and after that infection.

The comparison between younger adults aged 18 to 59 years and older adults aged 60 and above revealed a striking asymmetry. Younger recovered individuals showed robust CD4+ T cell activation following vaccination, with strong expansion of both spike-specific and non-spike-specific responses. Older adults, by contrast, exhibited attenuated responses overall, but the deficit was most pronounced in the non-spike compartment. Specifically, the frequency of Th1 cells among non-spike-specific CD4+ T cells was reduced in the older group. Th1 cells are the subset specialized for antiviral defense, characterized by their production of interferon-gamma, a cytokine that enhances viral antigen presentation, activates macrophages and supports cytotoxic lymphocyte function. A thinner Th1 layer against non-spike antigens means that a substantial portion of the viral proteome is met with a weaker cellular sentinel system in older vaccinees.

The memory phenotype of the responding cells also differed by age. Older adults carried a higher proportion of central memory cells among their antigen-specific CD4+ T cell populations. Central memory cells reside in lymphoid tissues and possess strong proliferative potential but slower effector function, whereas effector memory cells circulate in peripheral tissues and can act immediately upon antigen encounter. A memory pool skewed toward central memory may therefore provide a reserve of cells capable of expansion but a diminished first line of rapid effector defense at mucosal and tissue sites where SARS-CoV-2 initially replicates. This phenotypic shift adds a qualitative dimension to the age-related impairment, suggesting that it is not merely the quantity of responding cells but their differentiation state and tissue readiness that changes with age.

Functional output told a consistent story. When peripheral blood mononuclear cells from older participants were stimulated with non-spike peptide pools, they produced lower amounts of interferon-gamma than cells from younger participants. At the same time, they secreted higher levels of inflammatory cytokines including interleukin-10, interleukin-1 beta and interleukin-8. This combination is notable because it pairs a deficit in protective antiviral signaling with an excess of inflammatory output, a pattern consistent with the chronic low-grade inflammation of aging, sometimes called inflammaging. Interleukin-1 beta and interleukin-8 are associated with neutrophil recruitment and tissue inflammation, while interleukin-10 is an immunosuppressive cytokine that can dampen Th1 responses. Together, these shifts suggest that in older adults the response to vaccination is not simply weaker but qualitatively misdirected, favoring inflammation and regulation over targeted antiviral effector function.

A critical question was whether natural exposure to the Omicron variant could compensate for these vaccine-induced deficits. The answer, according to the study, was no. After participants experienced breakthrough infection with Omicron BA.5.2 or BF.7, the age-associated impairments persisted. Older adults showed compromised CD4+ T cell recall responses and a blunted expansion of non-spike-specific Th1 cells compared with younger individuals undergoing the same infection. Breakthrough infection effectively acts as a natural booster dose, re-exposing the immune system to the full viral proteome rather than only the spike antigen contained in the vaccine. The fact that older immune systems failed to expand their non-spike Th1 compartment even after this full-antigen encounter indicates a durable, intrinsic limitation rather than a transient gap in antigen exposure.

The implications for vaccine design are significant. Inactivated virus vaccines, which present the whole viral proteome to the immune system, were expected to elicit broad T cell recognition across spike and non-spike targets. The new data show that this breadth is achieved in younger adults but selectively lost in the non-spike Th1 compartment of older ones. Because Omicron variants carry numerous spike mutations that erode antibody neutralization, non-spike-specific T cell immunity has been proposed as a correlate of protection against severe disease that is more variant-resilient. If older adults cannot generate or recall these responses efficiently, they may remain vulnerable to severe outcomes despite vaccination, prior infection or both. The authors argue that their findings underscore the need for age-tailored vaccine strategies, which could include adjuvants that skew responses toward Th1 differentiation, higher antigen doses, alternative delivery platforms or booster formulations specifically designed to strengthen cellular immunity in older populations.

The study also contributes methodologically to a field that has often relied on antibody titers as the primary measure of vaccine success. By applying activation-induced marker assays longitudinally and dissecting T helper subsets, memory phenotypes and cytokine profiles, the researchers provide a template for evaluating cellular immunity with the granularity that correlates increasingly appears to demand. Their work was approved by the ethics committee of the Fifth Medical Center of Chinese PLA General Hospital, with written informed consent from all participants, and was funded by the National Key Research and Development Program of China, the National Natural Science Foundation of China and the Beijing Nova Program.

As populations age and SARS-CoV-2 continues to circulate and evolve, understanding precisely where immunity fails in older adults becomes a central task for vaccinology. This study localizes that failure with unusual clarity: not in the recognition of spike, and not in the raw presence of memory cells, but in the magnitude and functional polarization of Th1 responses against non-spike antigens, a defect that withstands both vaccination and natural reinfection. Closing that gap, whether through redesigned vaccines, targeted adjuvants or booster schedules calibrated to immune aging, may prove essential to extending the durable protection that younger immune systems achieve almost automatically.

Subject of Research: Age-related impairment of non-spike-specific Th1 CD4+ T cell responses to inactivated SARS-CoV-2 vaccination and Omicron breakthrough infection in recovered older adults

Article Title: Impaired non-spike-specific Th1 CD4+ T cell responses to inactivated SARS-CoV-2 vaccines and Omicron breakthrough infection in older individuals who had recovered from COVID-19

Article References: Fan, X., Tian, J., Zhang, B., Wang, J., Guo, Q., Guo, N., Li, X., Wang, G., Zhou, M.-J., Song, J.-W., Song, L., Mo, Q., Ni, W., Li, X., Zhou, L., Xu, X., Zhang, C., Wang, F.-S., & Huang, L. (2026). Impaired non-spike-specific Th1 CD4+ T cell responses to inactivated SARS-CoV-2 vaccines and Omicron breakthrough infection in older individuals who had recovered from COVID-19. Journal of Translational Medicine. https://doi.org/10.1186/s12967-026-09062-5

Image Credits: AI Generated

DOI: 10.1186/s12967-026-09062-5

Keywords: SARS-CoV-2, COVID-19, CD4+ T cells, Th1 cells, inactivated vaccines, Omicron breakthrough infection, aging, immunosenescence, inflammaging, T cell memory, interferon-gamma, vaccine strategy

Zbtb44 belongs to the ZBTB family of transcription factors, a group of proteins defined by an array of zinc fingers that grip specific DNA sequences and a BTB protein-interaction domain that recruits regulatory machinery. Family members such as PLZF, Bcl-6, ThPOK and Miz-1 have well-documented roles in lymphocyte development and function, but Zbtb44 had remained largely uncharacterized in the immune system. Prior hints of its importance came from cancer genetics, where a ZBTB44-FLT3 fusion gene was reported in a patient with a myeloproliferative neoplasm. The new work is among the first to assign the protein a clear physiological job: keeping the inflammatory output of T cells within safe limits in the intestinal tract.

The researchers generated mice in which the Zbtb44 gene was deleted and observed that these animals, as they aged, developed spontaneous inflammation of the colon severe enough to cause weight loss and rectal prolapse. Importantly, younger Zbtb44-deficient mice showed normal T cell development in the thymus, spleen and lymph nodes, indicating that the protein is not required to build the immune system but rather to discipline it. Heterozygous animals carrying a single functional copy of the gene did not develop spontaneous colitis, and co-housing experiments showed that the disease could not be transmitted to wild-type cage mates through the microbiota. Sequencing of fecal 16S ribosomal RNA revealed no dramatic shifts in bacterial community composition that could explain the phenotype, pointing instead to an intrinsic defect within the immune compartment.

That intrinsic defect centered on a single, familiar culprit: interferon-gamma. T cells lacking Zbtb44 produced markedly elevated amounts of this potent pro-inflammatory cytokine, a signaling molecule that is strongly associated with human inflammatory bowel disease. Interferon-gamma is classically the signature product of Th1 lineage T cells, whose differentiation is directed by the transcription factor T-bet, and it drives epithelial barrier dysfunction, chemokine production and macrophage activation in the intestinal wall. Using mass cytometry and flow cytometry, the team documented excess interferon-gamma production across CD4-positive and CD8-positive T cell populations in the knockout mice, including after infection with lymphocytic choriomeningitis virus, showing that the derepression is not confined to a single activation context.

To determine whether the excess interferon-gamma was merely a byproduct or the actual driver of disease, the investigators turned to loss-of-function and transfer experiments. When interferon-gamma was neutralized or absent, the severe colitis in Zbtb44-deficient mice was substantially ameliorated, in both chemically induced models and in adoptive transfer settings where naive T cells are introduced into lymphocyte-deficient recipients. Conversely, the colitis phenotype followed the T cells: mice lacking T cells altogether did not develop the spontaneous disease, and the pathology reconstituted when Zbtb44-deficient T cells were transferred in. Together these results establish a causal chain in which Zbtb44 loss unleashes T cell interferon-gamma, and unrestrained interferon-gamma in turn destroys the colonic epithelium.

The mechanistic heart of the paper lies in how Zbtb44 finds and silences the interferon-gamma gene, known as Ifng. Chromatin profiling using CUT&RUN, a technique that maps protein-DNA interactions with base-pair precision, revealed that Zbtb44 binds directly to the Ifng promoter and to regulatory enhancer elements within the locus. RNA sequencing confirmed that in the absence of Zbtb44, transcription from these sites increases, and CRISPR-based interference targeting the Zbtb44 binding sites in the Ifng locus reproduced the elevated cytokine expression even in otherwise normal cells. The data place Zbtb44 squarely in the small but growing category of dedicated silencers of the interferon-gamma gene, alongside elements such as the distal CNS-28 silencer described in earlier work, and highlight how the architecture of repression at this locus safeguards tissue homeostasis.

Perhaps the most surprising discovery concerns how Zbtb44 is recruited to its target. The team found that Zbtb44 undergoes SUMOylation, a post-translational modification in which a small ubiquitin-like modifier peptide is covalently attached to the protein. This modification enables Zbtb44 to engage a conserved SUMO-interacting motif within T-bet, the master transcription factor of Th1 cells. In effect, the repressor and the activator physically partner at the interferon-gamma promoter and enhancer, with Zbtb44 riding on T-bet to dampen the very program that T-bet initiates. When SUMOylation was disrupted, the interaction collapsed, Zbtb44 could no longer restrain the locus, and interferon-gamma production soared. This SUMO-dependent repressor-activator pairing offers an elegant explanation for how chronic cytokine output is kept in check even in cells committed to an inflammatory fate.

The study also connected the mouse findings to human disease. Single-cell RNA sequencing analyses of colon biopsy samples from patients with ulcerative colitis showed Zbtb44 expression in CD8-positive T cells and natural killer cell populations within inflamed tissue, suggesting that the regulatory circuit the researchers dissected in mice operates in the human gut as well. Given that interferon-gamma contributes to epithelial barrier breakdown and to the IL-23-driven inflammatory axis implicated in Crohn’s disease, a transcriptional brake on this cytokine represents an attractive node for intervention. Current cytokine-targeting strategies in inflammatory bowel disease, including antibodies against tumor necrosis factor, interleukin-12/23 and integrins, leave many patients undertreated, and the identification of intracellular repressors opens the possibility of small-molecule approaches that modulate SUMOylation or protein-protein interactions rather than blocking cytokines extracellularly.

Caveats remain before such translational ambitions can be realized. The work was performed predominantly in mice, and the precise contribution of Zbtb44 variants to human inflammatory bowel disease susceptibility has not been established through genetic association studies. SUMOylation touches hundreds of cellular substrates, so systemically manipulating the pathway carries broad risks, and any therapeutic strategy would need to achieve specificity for the T cell compartment. Nevertheless, the study delivers a conceptually satisfying message: the immune system depends not only on transcriptional activators that launch inflammatory programs but equally on repressors that keep those programs from running amok. With Zbtb44 now identified as a key SUMO-dependent silencer of interferon-gamma, researchers have a new molecular handle on one of the most consequential cytokines in intestinal immunity, and a fresh answer to the long-standing question of how the gut tolerates its teeming microbial residents without succumbing to self-destruction.

Subject of Research: Transcriptional repression of T cell interferon-gamma by Zbtb44 in colonic inflammation

Article Title: Zbtb44-mediated transcriptional repression critically regulates colonic inflammation

Article References: Kathania, M., Raj, D., Govindarajan, T., Raju, D. R., Verma, A. K., Roy, A., Mathur, R., Woody, J., Singh, A. K., Ahn, C., Patel, S., Yin, J., Lemoff, A., Theiss, A. L., Xing, C., Wu, T., Burstein, E., & Venuprasad, K. (2026). Zbtb44-mediated transcriptional repression critically regulates colonic inflammation. Nature Immunology. https://doi.org/10.1038/s41590-026-02675-4

Image Credits: AI Generated

DOI: 10.1038/s41590-026-02675-4

Keywords: Zbtb44, transcription factor, colitis, interferon-gamma, T-bet, SUMOylation, T cells, inflammatory bowel disease, Nature Immunology, immune regulation, mucosal immunology, transcriptional repression

The rationale for the study emerged from a persistent clinical observation: many patients with schizophrenia report gastrointestinal complaints, and multiple surveys have documented altered gut microbiome compositions in affected individuals. What has been missing is a causal account of how such microbial shifts could translate into neural dysfunction. Correlation alone cannot settle whether dysbiosis is a driver of symptoms, a side effect of antipsychotic medication, or a consequence of lifestyle differences. The Coimbra team therefore designed a transplantation experiment in which gut microbiota from schizophrenia patients was introduced into wild-type BALB/cByJ mice, allowing the researchers to observe, under controlled conditions, what the microbial community alone could do to a healthy host.

The results were striking. Mice receiving the schizophrenia-derived microbiota developed ileal dysbiosis, meaning their own gut bacterial communities became disturbed in ways resembling the donor profile. This was accompanied by inflammation in the intestine and disruption of the intestinal barrier, the tightly regulated epithelial lining that normally prevents bacteria and their products from leaking into the bloodstream. Barrier breakdown is a critical event because it permits microbial molecules and immune signals to travel beyond the gut, potentially influencing distant organs including the brain. The finding establishes the gut as a plausible point of origin for systemic disturbances previously observed in schizophrenia without pinpointing a mechanism.

That mechanism began to come into focus when the researchers examined the immune systems of the recipient mice. Animals carrying the schizophrenia microbiota showed elevated circulating levels of the pro-inflammatory cytokines interleukin-17 and interferon-gamma, alongside a reduction in CD4 T cells and a decreased CD4-to-CD8 ratio. Together, these signatures point to a Th17/Th1-skewed immune profile, a pattern in which helper T cell lineages that promote inflammatory responses become disproportionately activated. Th17 cells, named for their production of interleukin-17, are known to be particularly adept at breaching epithelial barriers and communicating with the nervous system, while Th1-driven interferon-gamma signaling is a hallmark of chronic inflammatory states. The immune fingerprint induced by the transplanted microbes closely resembles inflammatory abnormalities that clinicians and researchers have repeatedly documented in subsets of schizophrenia patients.

Most provocatively, the immune disturbances did not remain confined to the periphery. The mice exhibited microglial activation in the prefrontal cortex, a brain region central to working memory, decision-making, and social behavior, all of which are impaired in schizophrenia. Microglia are the resident immune cells of the central nervous system, and when activated they release cytokines and other mediators that can perturb neuronal function and synaptic maintenance. Consistent with this, the animals showed deficits in synaptic proteins, suggesting that the inflammatory environment was eroding the molecular infrastructure of neural communication. Behavioral testing confirmed functional consequences: the mice displayed hyperactivity, impaired working memory, and reduced social interaction, a triad that overlaps with core symptom domains of the human disorder.

A crucial strength of the study is that it did not rely on the mouse model alone. The researchers conducted post-mortem analyses of brain tissue from schizophrenia patients and found that the human brains recapitulated the key findings from the animals: increased microglial activation and elevated pro-inflammatory cytokine levels in the prefrontal cortex. This convergence between an experimentally induced phenotype and human neuropathology substantially strengthens the argument that the gut-immune-brain pathway the team mapped in mice is relevant to the actual biology of the disease, rather than an artifact of the transplantation procedure or the laboratory environment.

The technical design of the work reflects careful attention to confounders that have undermined earlier microbiome studies. By using wild-type mice rather than genetically modified or germ-free animals, the researchers tested whether patient-derived microbes could perturb an intact, normal immune and nervous system, a more demanding test than showing effects in a sensitized host. Human samples were obtained with informed consent under approved ethics protocols from Coimbra University Hospital, and post-mortem brain tissue came from the Neurological Tissue Bank of the Biobanco Hospital Clínic-IDIBAPS in Barcelona. Animal procedures complied with European Union and Portuguese legislation and were overseen by institutional welfare committees, ensuring that the translational claims rest on methodologically defensible ground.

The implications for treatment are potentially far-reaching. If gut dysbiosis contributes to the immune and synaptic pathology of schizophrenia, then microbiota-targeted interventions, including dietary modification, probiotics, prebiotics, or in more speculative scenarios fecal microbiota transplantation, could offer adjunctive therapies that complement existing antipsychotic medications. Current drugs largely address positive symptoms such as hallucinations and delusions while leaving cognitive deficits and negative symptoms poorly treated. A therapeutic avenue aimed at calming intestinal inflammation and rebalancing immune signaling might, in principle, reach aspects of the illness that dopamine-targeting drugs cannot. The authors frame their findings as providing a conceptual framework for such microbiota-targeted strategies, while the data themselves stop short of demonstrating that correcting dysbiosis reverses any aspect of the disease.

Important caveats remain. The study shows that schizophrenia-associated microbiota can induce disease-relevant changes in mice, but it does not establish that gut bacteria initiate schizophrenia in humans, nor does it identify which specific microbial species or strains carry the pathogenic potential. Schizophrenia is a heterogeneous condition, and the patients whose microbiota was transplanted may have shared environmental, dietary, or medication-related factors that shaped their gut communities. Whether the observed microglial activation and synaptic protein deficits in mice arise through microbial metabolites, immune cell trafficking, or vagal nerve signaling is a question the study leaves open for future work. Longitudinal studies in patients, along with experiments identifying the responsible microbial components, will be needed to convert this mechanistic framework into clinical practice.

Nevertheless, the study marks a significant advance in a field that has often been accused of overpromising. By connecting a human-derived microbial community to specific immune signatures, defined brain-region pathology, measurable synaptic changes, and quantifiable behavioral abnormalities, and then validating the brain findings in human post-mortem tissue, the Coimbra team has assembled a coherent mechanistic chain from gut to brain. For a disorder that affects roughly one in every hundred people worldwide and remains one of the leading causes of disability, any new biological handle is welcome. The message of this research is that the brain in schizophrenia may not be sick alone; the gut, the immune system, and the resident microbes of the digestive tract appear to be part of the conversation, and learning to listen to that conversation could reshape how the illness is understood and treated.

Subject of Research: The role of the gut microbiome-immune-brain axis in the pathophysiology of schizophrenia

Article Title: Unveiling the gut microbiome-immune-brain axis in schizophrenia

Article References: Pereira-Santos, A. R., Candeias, E., Maranha, A., Esteves, A. R., Alarico, S., Tiago, I., Bajouco, M., Madeira, N., Empadinhas, N., & Cardoso, S. M. (2026). Unveiling the gut microbiome-immune-brain axis in schizophrenia. Translational Psychiatry. https://doi.org/10.1038/s41398-026-04497-2

Image Credits: AI Generated

DOI: 10.1038/s41398-026-04497-2

Keywords: schizophrenia, gut microbiome, gut-brain axis, microglial activation, Th17 cells, interleukin-17, interferon-gamma, prefrontal cortex, intestinal barrier, synaptic proteins, neuroinflammation, microbiota transplantation