Journal of immunology最新文献

{"title":"IgA binding characteristics of golden hamster and ferret Fcα receptors.","authors":"Xiaoxuan Ge, Matthew R Stoner, Joshua A Weiner, Sarah S Parigela, Melanee E Balderas Hernández, Noor Taher, Jiwon Lee, Margaret E Ackerman","doi":"10.1093/jimmun/vkag218","DOIUrl":"10.1093/jimmun/vkag218","url":null,"abstract":"<p><p>Golden hamster (Mesocricetus auratus) and ferret (Mustela putorius furo) are important animal models in studies of human infectious disease. They are used widely to investigate pathogen-spreading mechanisms and host immunology to evaluate the safety and efficacy of small molecules, biologic drugs and vaccines. To this end, immunoglobulin A (IgA) and its Fcα receptor (FcαR) play critical roles in humans but are not well characterized in these 2 species. Golden hamster and ferret IgA and FcαR were recombinantly expressed, purified, and characterized for N-linked glycosylation site occupancy and binding affinity. Based on sequence and structural alignments, hamster IgA showed greater similarity to human IgA than did ferret, and hinge domains in both small animal models suggested greater structural homology to human IgA2 than IgA1. Despite considerable sequence divergence in both immunoglobulins and receptors, and the lack of binding between ferret FcαR and ferret IgA, human IgA bound to both hamster and ferret FcαR with high affinity. Further, differences in dissociation rates were dependent on test format, suggesting that the 2:1 stoichiometry of human FcαR: IgA is recapitulated in these animals. Overall, this work suggests the suitability of these animals to model protection or pathology driven by interactions between human IgA and host FcαR and will aid in critical and confident interpretation of infection and immunization studies in each species.</p>","PeriodicalId":16045,"journal":{"name":"Journal of immunology","volume":"215 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13548764/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148689307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adipose stem cell vesicles reduce bleomycin-induced dermal fibrosis and oxidative stress in scleroderma mice via circ-Zfyve9.","authors":"Xue Li, Weiguo Zhang, Jiao Liu, Zhidong Zhu, Hui Tang, Yiqi Zhu, Hao Wang, Mingming Jin, Gang Huang, Qingqing Huang","doi":"10.1093/jimmun/vkag219","DOIUrl":"https://doi.org/10.1093/jimmun/vkag219","url":null,"abstract":"<p><p>Systemic sclerosis (SSc) is an autoimmune condition affecting several organs. It is identified by thickening of the dermis, connective tissue affected by collagen accumulation, and vascular injuries that induce hypoxia. The present study aimed to determine whether extracellular vesicles (EVs) from adipose-derived stem cells (ADSCs) attenuated bleomycin-induced skin fibrosis and oxidative stress in scleroderma. ADSCs and their EVs were separated and a bleomycin-induced SSc mouse model was constructed. High-throughput sequencing was employed to study abnormal expression of circular RNAs in SSc skin tissues with or without ADSC-EV treatment. The regulatory mechanism and targets were studied using bioinformatics analysis, luciferase reporting analysis, angiogenic differentiation experiments, and RT-qPCR detection analysis. EVs from ADSCs were successfully isolated. The exosome treatment prevented dermal thickening and fibrosis in bleomycin-induced scleroderma. In addition, circ-Zfyve9 was demonstrated to have an important function in ADSC-EV-mediated skin tissue protection. GPX4 and miR-135 were shown to be downstream targets of circ-Zfyve9. Overexpressing miR-135 or downregulating GPX4 reversed the promotion effects of circ-Zfyve9 on angiopoiesis by increasing lipidosome ROS in EPCs under hypoxic conditions. Overexpressing miR-135 or downregulating GPX4 reversed the inhibition effect of circ-Zfyve9 on fibrosis in myofibroblasts under hypoxic conditions. Overexpressing circ-Zfyve9 increased the therapeutic effect of ADSC-EVs. EVs from ADSCs attenuated bleomycin-induced skin fibrosis and oxidative stress in scleroderma via circ-Zfyve9 delivery.</p>","PeriodicalId":16045,"journal":{"name":"Journal of immunology","volume":"215 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148760126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identifying molecular signatures underpinning treatment responses to novel therapeutics influencing COVID-19 outcomes.","authors":"Jodie Ackland, Victor Barozi, Rebekah Penrice-Randal, Catherine Hartley, Julian A Hiscox, Gareth Griffiths, Clive Page, Miles Carroll, Dave Singh, Mahesan Niranjan, Diana Baralle, Andres Vallejo Pulido, Tom Wilkinson","doi":"10.1093/jimmun/vkag189","DOIUrl":"https://doi.org/10.1093/jimmun/vkag189","url":null,"abstract":"<p><p>COVID-19 continues to present ongoing global health challenges driven by diverse immune responses and heterogeneous clinical outcomes. The ACCORD trial evaluated 3 investigational treatments-bemcentinib, tozorakimab, and zilucoplan-in patients hospitalized with COVID-19, each of which has demonstrated clinical efficacy. To better understand their molecular mechanisms, we conducted a mechanistic follow-up study, integrating transcriptomic and clinical data from 65 patients and applying cellular deconvolution, differential expression, coexpression, and pathway enrichment analyses to uncover treatment-specific immune responses. Each therapy induced transcriptional shifts and modulated distinct immune pathways implicated in severe disease. Bemcentinib primarily modulated myeloid cell populations and inflammatory signalling; zilucoplan enhanced B-cell signalling and lymphocyte-associated pathways; and tozorakimab exerted broad immune and cellular responses across immune cell types. Co-expression analysis revealed gene networks associated with clinical improvement, each driven by distinct treatment-specific hub genes, indicating diverse regulatory mechanisms across treatments. Improved outcomes correlated with gene expression shifts in 4 key immunological pathways: B-cell signalling, antiviral defense, innate inflammation, and platelet/coagulation activity. In contrast, nonresponders had persistent dysregulation of 1 or more of these gene signatures. Our findings define molecular signatures of treatment response and failure in COVID-19, providing mechanistic insight into how distinct therapies modulate the immune system. These insights support the need for adaptive precision medicine approaches tailored to individual, evolving immune trajectories. Moreover, the immunological mechanisms targeted by these repurposed immunomodulatory therapies may inform treatment strategies across a broader spectrum of immune-mediated diseases beyond COVID-19.</p>","PeriodicalId":16045,"journal":{"name":"Journal of immunology","volume":"215 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148689261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Age-related changes in the human T cell receptor alpha repertoire suggest positive selection of dual-specific T cells.","authors":"Juho Nummelin, Joonatan Mattila, Vera Middelkamp, Jari Saramäki, Nelli Heikkilä, T Petteri Arstila","doi":"10.1093/jimmun/vkag214","DOIUrl":"https://doi.org/10.1093/jimmun/vkag214","url":null,"abstract":"<p><p>The human T cell receptor (TCR) repertoire is generated in the thymus through a process of recombination involving two gene loci, TRA and TRB, and the pairing of the resulting peptide chains. Because of the lack of allelic exclusion in TRA loci, it is possible for a T cell to express either one or two distinct TRA chains, and although both configurations are present in significant quantities in the mature T-cell population, this has been viewed a largely inconsequential phenomenon. We analyzed human TRA repertoires using sequencing of genomic DNA as starting material from T-cell subsets representing different maturation stages of T cells, from donors aged from 7 d to 61 yr, some with chronic exposure to pathogen or autoimmune antigens. The frequency of productive TRA clonotypes increased along the T cell maturation stage and showed a consistent positive correlation with the donor age. Moreover, our data provide evidence of chronic antigen exposure further increasing the frequency of productive TRA sequences. We propose that these unexpected findings are due to a preferred positive peripheral selection of the T cell population bearing 2 functional TRA chains.</p>","PeriodicalId":16045,"journal":{"name":"Journal of immunology","volume":"215 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148794128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rapid glycolytic metabolism underpins mucosal-associated invariant T cell functional responses to innate cytokines.","authors":"Eimear K Ryan, Benjamin J Jenkins, Ronan Bergin, Rafael E Salazar, Cian Davis, Nidhi Kedia-Mehta, Ali Amini, Lucy C Garner, Ciara Flynn, Sinéad Ryan, Iain Perry, Joanne C Masterson, Helen Heneghan, Paul N Moynagh, Kirby N Swatek, Paul Klenerman, Nicholas Jones, Linda V Sinclair, Donal O'Shea, Andrew E Hogan","doi":"10.1093/jimmun/vkag212","DOIUrl":"10.1093/jimmun/vkag212","url":null,"abstract":"<p><p>Mucosal-associated invariant T (MAIT) cells express a semi-invariant T cell receptor (TCR) that recognizes bacterial-derived antigens presented on MR1. Upon TCR triggering, MAIT cells respond rapidly, producing a range of effector molecules which facilitate host-protective responses in the context of microbial infections. In contrast, MAIT cell responses to viral infection are instead triggered by the recognition of cytokines, and occur independently of TCR engagement. The molecular and metabolic regulation of MAIT cell TCR responses is rapidly emerging, but there is a paucity of data on cytokine driven responses. Here, using high-resolution, quantitative proteomic analysis, we map the downstream proteome of innate cytokine (IL-18/IFNα)-activated MAIT cells, highlighting robust cytokine-driven remodeling and a signature that is distinct from the TCR-driven response. MAIT cells significantly increase protein biosynthesis in response to innate cytokine stimulation and rapidly upregulate the production of IFNγ, granzyme B, and IFN-stimulated gene 15. We demonstrate the metabolic kinetics of MAIT cell responses to cytokine stimulation and highlight a rapid but transient glycolytic burst that is uncoupled from mitochondrial remodeling and contrasts the robust metabolic profile elicited downstream of TCR engagement. Finally, we demonstrate differential contributions from both glycogen and glucose in supporting MAIT cell responses to innate cytokines and further highlight the importance of nutrient availability as a governing signal for MAIT cell fitness and effector functioning.</p>","PeriodicalId":16045,"journal":{"name":"Journal of immunology","volume":"215 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148722805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metabolic crosstalk between c-Myc and glutamine utilization sustains IgM+ B-cell immunity in teleosts.","authors":"Xinying Jiao, Yating Zhu, Kang Li, Ming Geng, Jiansong Zhang, Yuying Zheng, Qiqi Jiang, Haokai Chen, Jialong Yang, Xiumei Wei","doi":"10.1093/jimmun/vkag227","DOIUrl":"https://doi.org/10.1093/jimmun/vkag227","url":null,"abstract":"<p><p>B-cell responses rely on a tightly coordinated interplay between transcriptional programs and metabolic reprogramming. Upon activation, B cells remodel their metabolic profiles, with enhanced glutamine metabolism supporting biomass synthesis and proliferation. However, whether and how glutaminolysis underpins B-cell responses in early vertebrates remains largely unexplored. Here, using the Nile tilapia (Oreochromis niloticus) as a model, we demonstrate that IgM+ B cells markedly increase glutamine utilization upon activation. Glutamine deprivation impaired B-cell activation and proliferation, whereas glutamine supplementation promoted these processes. During Edwardsiella piscicida infection, pharmacological inhibition of glutamine metabolism significantly reduced the expansion of IgM+ B cells and compromised antibody secretion. Mechanistically, glutamine metabolism in tilapia IgM+ B cells was governed by the transcription factor c-Myc. Inhibition of c-Myc disrupted glutaminolysis, leading to diminished B-cell proliferation and antibody production. Upon activation, IgM+ B cells coordinated c-Myc expression and downstream glutamine metabolism through the mTORC1 and ERK signaling pathways, thereby coordinating metabolic and immune functions. Notably, this regulatory mechanism operated in a B cell-intrinsic manner and was independent of T-cell help. Collectively, our findings reveal that teleost B cells possess evolutionarily conserved and sophisticated immunometabolic regulatory programs. This study provides new insights into how metabolic pathways are integrated with immune signaling to control B-cell function, highlighting coordinated immunometabolic regulation as a fundamental mechanism underlying vertebrate B-cell immunity.</p>","PeriodicalId":16045,"journal":{"name":"Journal of immunology","volume":"215 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148706871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fluid shear stress as a co-stimulatory cue to enhance T cell priming and restore activation in cancer patient T cells.","authors":"Nicole S Sarna, Monika Antunovic, Paula J Hurley, Kerry R Schaffer, Michael R King","doi":"10.1093/jimmun/vkag166","DOIUrl":"10.1093/jimmun/vkag166","url":null,"abstract":"<p><p>Cancer patient-derived T cells often exhibit impaired activation and functional responsiveness due to chronic antigen exposure and therapy-induced immune dysregulation, limiting the efficacy of current immunotherapies. Mechanical forces, such as fluid shear stress (FSS), are emerging as critical regulators of immune cell activation, yet their role in modulating activation of patient-derived T cells remains largely unexplored. In this study, primary T cells isolated from patients with metastatic prostate cancer were exposed to FSS using a cone-and-plate viscometer during ex vivo activation in the presence and absence of bead-bound anti-CD3/CD28 monoclonal antibodies. FSS alone was sufficient to induce NF-κB phosphorylation and intracellular cytokine synthesis, demonstrating that mechanical stimulation can independently initiate T cell activation signaling. Moreover, FSS combined with anti-CD3/CD28 stimulation produced a synergistic increase in activation signaling, IL-2 and IFN-γ production, and CD25/CD69 expression. While trends were consistent across donors overall, inter-patient variability reflected differences in baseline T cell phenotype, with naïve-like cells displaying greater mechanosensitivity. These results indicate that cancer patient-derived T cells retain mechanotransduction capacity despite reduced antigen responsiveness. Incorporating FSS as a co-stimulatory signal during ex vivo expansion may be more effective at priming patient T cells for activation, enhancing effector function, and improving the efficacy of adoptive cell therapies.</p>","PeriodicalId":16045,"journal":{"name":"Journal of immunology","volume":"215 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13445966/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148678821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CD55 downregulation identifies a pathogenic CD4+ T cell axis linked to p38 MAPK signaling in rheumatoid arthritis.","authors":"Ayibaota Bahabayi, Yiming Gao, Ziqi Xiong, Xiaochen Sun, Qi Li, Zhonghui Zhang, Guochong Wang, Chen Liu","doi":"10.1093/jimmun/vkag229","DOIUrl":"https://doi.org/10.1093/jimmun/vkag229","url":null,"abstract":"<p><p>CD4+ T cell dysfunction plays a critical role in the pathogenesis of rheumatoid arthritis (RA). In this study, we investigated the expression, phenotypic characteristics, and potential clinical significance of CD55, a membrane-bound complement regulatory protein, in peripheral blood CD4+ T cells from RA patients. Flow cytometric analysis revealed that CD55 expression was highest in naive CD4+ T cells and was significantly reduced in patients with early RA compared with healthy controls. Functionally, CD55+CD4+ T cells displayed enhanced production of IL-17, IL-21, and IL-22 following stimulation and exhibited reduced susceptibility to complement deposition. Transcriptomic analysis identified distinct molecular signatures associated with CD55 expression, which were further validated at the protein level, including increased expression of PAX5, CR2, and CD248 in CD55+CD4+ T cells. In addition, CD55 expression was inversely associated with p38 MAPK activation, suggesting a link between CD55 downregulation and aberrant T cell activation. Receiver operating characteristic analysis demonstrated that CD55+CD4+ T cell frequency possessed diagnostic value for distinguishing patients with early RA from healthy controls and primary Sjögren's syndrome patients. Collectively, these findings identify CD55 as a marker of a distinct CD4+ T cell subset with altered functional and molecular characteristics and support its potential utility in the early diagnosis and differential diagnosis of RA.</p>","PeriodicalId":16045,"journal":{"name":"Journal of immunology","volume":"215 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148794066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Antigen presentation requirements for effective cDC1-based cancer immunotherapy.","authors":"Josué E Pineda, Tomoyuki Minowa, Li Shen, Yifan Zhou, Allison Dyevoich, Bhakti Patel, Sarah M Schneider, Sunita Keshari, Akata Saha, Morgan N Riba, Jing Wang, Stephanie S Watowich, Matthew M Gubin","doi":"10.1093/jimmun/vkag198","DOIUrl":"10.1093/jimmun/vkag198","url":null,"abstract":"<p><p>Type 1 conventional dendritic cells (cDC1s) are important for generating and sustaining antitumor immunity. Accordingly, the abundance of cDC1s in human tumors correlates with improved outcomes in cancer. Capitalizing on this role, we previously demonstrated that vaccination with murine cDC1s, generated in culture from bone marrow cells (termed here \"in vitro-derived cDC1s\"), elicits durable tumor control in multiple preclinical models; however, the immunological mechanisms underlying the efficacy of cDC1 vaccination remain unclear. Here, we examined whether in vitro-derived cDC1s resemble tumor-infiltrating DC populations and whether MHC-I and MHC-II antigen presentation contribute to cDC1-mediated tumor control following vaccination in melanoma. As expected, MHC-I or MHC-II deficiency had minimal impact on the transcriptional state of cDC1s in homeostasis or following stimulation with the adjuvant poly dI:dC. Moreover, in vitro-derived cDC1s cultured under steady-state conditions closely resembled tumor-infiltrating cDC1s, whereas their poly dI:dC-stimulated counterparts resembled CCR7+ tumor-infiltrating DC populations, also referred to as mregDCs or LAMP3+ DCs. Our data further show that both MHC-I and MHC-II contribute to tumor control upon cDC1 vaccination and that coexpression of MHC-I and MHC-II on the same cDC1 is necessary for a robust vaccine response. We also identified an important function for host cDC1s in supporting the efficacy of vaccination with in vitro-derived cDC1s, as judged by impaired tumor control in Irf8 + 32-/- mice, which lack endogenous cDC1s. Overall, these results indicate that effective antitumor responses depend on MHC-I and MHC-II antigen presentation by vaccine-delivered cDC1s, with additional contributions from host cDC1s.</p>","PeriodicalId":16045,"journal":{"name":"Journal of immunology","volume":"215 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13470371/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148723511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generation and characterization of a novel MHC-II tetramer for tracking and characterization of toxin B-specific CD4+ T cell responses.","authors":"Jeffrey R Maslanka, Qianxuan She, Kathleen S Krauss, Emily N Bitsko, Nile U Bayard, Jennifer A Londregan, Mohamad-Gabriel Alameh, Laurence C Eisenlohr, Michele A Kutzler, Joseph P Zackular, Michael C Abt","doi":"10.1093/jimmun/vkag152","DOIUrl":"10.1093/jimmun/vkag152","url":null,"abstract":"<p><p>The gastrointestinal pathogen Clostridioides difficile is a major burden for health systems due to high rates of recurrence. C. difficile pathogenesis is mediated by two virulence factors, toxin A (TcdA) and toxin B (TcdB). Antibodies specific for TcdA and TcdB are correlated with protection from symptomatic recurrence; however, the role for CD4+ T cells is poorly understood in part due to the lack of tools to study the toxin-specific CD4+ T cell response. Our group recently demonstrated the antibody and CD4+ T cell response to C. difficile toxins is impaired via the glucosyltransferase activity of the toxins; however, tools do not exist to study the protective capacity and the phenotype of toxin-specific CD4+ T cells. Therefore, we developed a major histocompatibility complex class II (MHC-II) tetramer to identify TcdB-specific CD4+ T cells via flow cytometry. Herein, we identified an immunodominant epitope (TcdB1961-1975) in the CROPs region of TcdB and optimized an MHC-II tetramer for use in tracking and phenotyping TcdB-specific CD4+ T cell responses following multiple different immunization strategies in mice. Utilizing the tetramer, TcdB-specific T follicular helper cells were detected following TcdB-CROPs messenger RNA lipid nanoparticle vaccination validating the advantage of the tetramer. Furthermore, using a modular messenger RNA vector expressing the TcdB1961 peptide covalently bound to the beta chain of MHC-II, we were able to generate a robust population of TcdB-specific CD4+ T cells. These data outline the generation of new tools for the C. difficile field and lay the groundwork for future studies of toxin-specific CD4+ T cell responses.</p>","PeriodicalId":16045,"journal":{"name":"Journal of immunology","volume":"215 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148759944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}