scholarly journals Vaccine serologic responses among transplant patients associate with COVID-19 infection and T peripheral helper cells

2021 ◽  
Author(s):  
Jacob E. Lemieux ◽  
Amy Li ◽  
Matteo Gentili ◽  
Cory A. Perugino ◽  
Zoe F. Weiss ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Cd4 T Cells ◽  
Lung Transplant ◽  
T Cell Subsets ◽  
Healthy Controls ◽  
Transplant Recipients ◽  
Vaccine Response ◽  
Lung Transplant Recipients

Background: Therapeutically immunosuppressed transplant recipients exhibit attenuated responses to COVID-19 vaccines. To better understand the immune alterations that determined poor vaccine response, we correlated quantities of circulating T and B cell subsets at baseline with longitudinal serologic responses to SARS-CoV-2 mRNA vaccination in heart and lung transplant recipients. Methods: Samples at baseline and at approximately 8 and 30 days after each vaccine dose for 22 heart and lung transplant recipients with no history of COVID-19, four heart and lung transplant recipients with prior COVID-19 infection, and 12 healthy controls undergoing vaccination were analyzed. Anti-spike protein receptor binding domain (RBD) IgG and pseudovirus neutralization activity were measured. Proportions of B and T cell subsets at baseline were comprehensively quantitated. Results: At 8-30 days post vaccination, healthy controls displayed robust anti-RBD IgG responses, whereas heart and lung transplant recipients showed minimally increased responses. A parallel absence of activity was observed in pseudovirus neutralization. In contrast, three of four (75%) transplant recipients with prior COVID-19 infection displayed robust responses at levels comparable to controls. Baseline levels of activated PD-1+ HLA-DR+ CXCR5- CD4+ T cells (also known as T peripheral helper [TPH] cells) and CD4+ T cells strongly predicted the ability to mount a response. Conclusions: Immunosuppressed patients have defective vaccine responses but can be induced to generate neutralizing antibodies after SARS-CoV-2 infection. Strong correlations of vaccine responsiveness with baseline TPH and CD4+ T cell numbers highlights a role for T helper activity in B cell differentiation into antibody secreting cells during vaccine response.

Therapy of B Cell Malignancies with CD19-Specific Chimeric Antigen Receptor-Modified T Cells of Defined Subset Composition

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 384-384 ◽  
Author(s):  
Cameron J Turtle ◽  
Daniel Sommermeyer ◽  
Carolina Berger ◽  
Michael Hudecek ◽  
David M Shank ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Cd4 T Cells ◽  
Research Funding ◽  
T Cell Subsets ◽  
B Cell Malignancies ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T

Abstract BACKGROUND: The adoptive transfer of CD19-specific chimeric antigen receptor-modified (CD19 CAR) T cells is a promising strategy for treating patients with CD19+ B cell acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), and non-Hodgkin lymphoma (NHL). Dramatic responses have been observed in a subset of patients receiving CD19 CAR T cell therapy, and prior studies suggest that persistence of transferred T cells may correlate with the extent of tumor regression. The use of unselected T cells to prepare CAR T cells results in variation in the phenotypic composition of the infused product in individual patients, making it difficult to determine whether particular T cell subsets contribute to efficacy and/or toxicity. Studies in our lab demonstrated that genetically modified effector T cells derived from purified T cell subsets differ in the capacity to persist in vivo after adoptive transfer, and that a combination of CAR-modified CD8+ central memory (TCM) and CD4+ T cells provides optimal antitumor activity in tumor xenograft models. Based on these data, we designed the first clinical trial in which patients with CD19+ B cell malignancies receive CD19 CAR T cells comprised of a defined composition of CD8+ TCM and CD4+T cells engineered to express a CD19 CAR. METHODS: Patients with relapsed or refractory CD19+ ALL, CLL or NHL are eligible for this phase I/II study. CD8+ TCM and CD4+ T cells were separately enriched by immunomagnetic selection from a leukapheresis product from each patient, and cryopreserved. The CD8+ TCM and CD4+ T cells were stimulated in independent cultures with anti-CD3/anti-CD28 paramagnetic beads, and transduced with a lentivirus encoding the murine FMC63 anti-CD19 scFv, 4-1BB and CD3 zeta signaling domains. After in vitro expansion, the cell product for infusion was formulated in a 1:1 ratio of CD4+:CD8+ CAR+ T cells. A truncated non-functional human epidermal growth factor receptor (EGFRt) encoded in the transgene cassette allowed identification of transgene-expressing T cells by flow cytometry. Lymphodepleting chemotherapy was administered followed by infusion of EGFRt+ CAR T cells at one of three dose levels (2 x 105 EGFRt+ cells/kg, 2 x 106 EGFRt+ cells/kg, 2 x 107 EGFRt+cells/kg). RESULTS: Twenty patients with relapsed or refractory ALL (n = 9), NHL (n = 10) or CLL (n = 1), including those who failed prior autologous (n = 4) or allogeneic (n = 4) stem cell transplant have been treated on the trial. Fifteen of 20 treated patients received a product that conformed to the prescribed CD8+ T­CM:CD4 composition. Five patients received a product manufactured using a modified strategy either due to low blood lymphocyte counts (n = 3) or due to failure to propagate T cells in culture (n = 2). CD8+ TCM and CD4+ T cells have been isolated from 12 additional patients and cryopreserved for therapy. Patients have been treated at all three dose levels without acute infusional toxicity. Severe cytokine release syndrome (sCRS) consisting of fever, hypotension, and reversible neurotoxicity associated with elevated serum IFN-γ and IL-6 was only observed in ALL patients with a high tumor burden. One ALL patient treated at the highest cell dose died of complications associated with sCRS. None of the NHL patients had sCRS. Of patients who are >6 weeks after CD19 CAR T cell therapy, best responses included complete (n=1) or partial (n=5) remission in 6/9 patients with NHL and complete remission in 5/7 patients with ALL. Both CD4+ and CD8+ CAR-T cells expanded in vivo and could be detected in blood, marrow and CSF. The peak level and duration of persistence of both CD4+ and CD8+ EGFRt+ T cells were associated with clinical response. TCRBV gene sequencing of flow sorted CD4+ and CD8+ EGFRt+CAR T cells from 2 patients showed that proliferating CAR T cells were polyclonal. A subset of NHL patients in whom CAR T cells became undetectable developed a T cell immune response to sequences in the murine CD19-specific scFv component of the CAR transgene. CONCLUSION: Adoptive immunotherapy with CD19 CAR T cells of defined subset composition is feasible and safe in a majority of heavily pretreated patients with refractory B cell malignancies and has potent anti-tumor activity. Persistence of CAR-T cells may be limited in some patients by transgene product immunogenicity. Data from this ongoing clinical trial will be updated at the meeting. Disclosures Turtle: Juno Therapeutics: Research Funding. Berger:Juno Therapeutics: Patents & Royalties. Hudecek:Juno Therapeutics: Patents & Royalties. Jensen:Juno: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Riddell:Juno Therapeutics: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Maloney:Juno Therapeutics: Research Funding.

B Cell With Regulatory Function Are Enriched Within Transitional and IgM Memory B Cell Subsets In Healthy Donors But Are Reduced and Functionally Impaired In Patients With Chronic Graft-Versus-Host Disease

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4478-4478
Author(s):  
Anushruti Sarvaria ◽  
Ahmad Khoder ◽  
Abdullah Alsuliman ◽  
Claude Chew ◽  
Takuya Sekine ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cd4 T Cells ◽  
Memory B Cells ◽  
Regulatory Function ◽  
Healthy Controls ◽  
Transitional B Cells ◽  
B Cell Subsets

The immunosuppressive function of IL10 producing regulatory B cells (Bregs) has been shown in several murine models of inflammation and autoimmune disease. However, there is a paucity of data regarding the existence of an equivalent regulatory B cell subset in healthy individuals and their potential role in the pathogenesis of chronic graft-versus-host disease (cGVHD) remains unknown. Here, we examined the functional regulatory properties of peripheral blood (PB)-derived human B cell subsets from healthy individuals. In addition, we carried out studies to explore their role in cGVHD, using B cells from patients following allogeneic stem cell transplantation (HSCT). We first determined whether human IL-10 producing B cells are enriched within any othe previously described human B cell subsets: CD19+IgM+CD27+ IgM memory, CD19+IgM-CD27+ switched memory, CD19+IgM+CD27- naive, and and transitional CD19+CD24hiCD38hi. Following in vitro stimulation with CD40 ligand, the majority of IL-10 producing B cells were found within the CD24hiCD38hi transitional and CD19+IgM+CD27+B cell subsets. We next assessed the regulatory properties of the PB-derived B cell subsets, by sort-purifying IgM memory (CD19+IgM+CD27+), switched memory (CD19+IgM-CD27+), naïve (CD19+IgM+CD27-) and transitional (CD19+CD24hiCD38hi) B cells from healthy controls, and cultured them 1:1 with autologous magnetic-bead purified CD4+ T cells. CD3/CD28 stimulated CD4+ T cells cultured with either CD19+IgM+CD27- naïve or CD19+IgM-CD27+ switched memory B cells proliferated to the same extent and produced equivalent amounts of IFN-γ to cultures containing CD4+ T cells alone. In contrast, culture of CD4+ T cells with IgM memory and transitional B cells significantly suppressed CD4+ T cell proliferation [median percent proliferating CD4+ T cells 52.5%; (33%-75%)] and 51% (25%-63%)], respectively when compared with CD3/CD28 stimulated CD4+ T cells (positive control) [89.5% (75%-92%], p=0.0001. The inhibitory effect of IgM memory and transitional B cells on CD4+ T cell proliferation was cell dose dependent with the highest suppression observed at a ratio of 1:1. These data suggest that human PB transitional and IgM memory B cells are endowed with regulatory function. We next examined if the in vitro suppressive effect of transitional and IgM memory B cells is mediated by regulatory T cells (Tregs). For this purpose, CD4+ T cells were depleted of CD127lo CD25hi CD4+ T cells by magnetic cell purification. B cell subsets were cultured with CD3/CD28 stimulated CD4+ CD25- T cells at a ratio of 1:1. IgM memory and transitional B cells were able to significantly suppress the proliferation and Th1 cytokine response by CD4+ CD25- T cells compared to cultures containing CD4+ CD25-T cells alone, indicating that the suppressive activity of Bregs is independent of Tregs. To further understand the underlying mechanims though which Bregs exert T-cell suppression, we used antibody blockade experiments and showed that this suppressive effect was mediated partially via the provision of IL-10, but not TGF-ß. Using transwell experiments, we further determined that the suppressive function of Bregs is also partly dependent on direct T cell/B cell contact. We next assessed whether the activity of Breg cells might be altered in patients with cGVHD. B cells from patients with cGVHD were refractory to CD40 stimulation and produced less IL-10 when compared to patients without cGVHD post-SCT and healthy controls, [1.02% (0.22-2.26) vs.1.72% (0.8-5.52) vs. 2.16 (1.3- 5.6), p=0.001]. Likewise, the absolute number of IL-10 producing B cells was significantly lower in cGvHD patients compared to patients without cGVHD and healthy controls (p=0.007), supporting both a qualitative and quantitative defect in IL-10 producing B cells in cGvHD. Our combined studies provide important new data defining the phenotype of B cell populations enriched in regulatory B cells in healthy humans and provide evidence for a defect in the activity of such cells in patients with cGVHD post-SCT. In association with previous reports showing defects in Treg cell activity in GVHD, our results suggest the existence of a broad range of deficiencies in immune regulatory cell function in cGvHD patients. * Both Anushruti Sarvaria and Ahmad K contributed equally. Disclosures: No relevant conflicts of interest to declare.

Dysfunctional Tregs with Absence of Cytokine-Secreting CD4+ T-Cell Subsets and Marked Expansion of Th1 Cells Is a Hallmark of Idiopathic Aplastic Anaemia (AA)

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2233-2233
Author(s):  
Shahram Kordasti ◽  
Judith C. W. Marsh ◽  
Pilar Perez Abellan ◽  
Sufyan Alkhan ◽  
Janet Hayden ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Cd4 T Cells ◽  
Cytokine Secretion ◽  
T Cell Subsets ◽  
Cd4 T Cell ◽  
Th1 Cells ◽  
Healthy Controls ◽  
Ifn Γ

Abstract Abstract 2233 Introduction: Autoimmunity is an important contributor in the aetiology of AA. Although the expansion of oligoclonal CD8+ T-cells and their correlation with response to immunosuppressive therapy (IST) has been reported previously, the role of CD4+ in the pathogenesis is not elucidated. The focus of this study was to investigate the role of different CD4+ T-cell subsets, including regulatory T-cells (Tregs) and T helpers (Th1, Th2 and Th17) in the pathobiology of idiopathic AA. Patients and Methods: The percentage and absolute numbers of CD4+ and CD8+ T-cell subsets, NK & B cells and dendritic cells (DCs) in peripheral blood were assessed in 42 patients with idiopathic AA prior to any IST and 8 healthy age matched controls. T-cells were stimulated first and stained intracellularly for IFN-γ and TNF-a (Th1), IL-4 (Th2) and IL-17 (Th17). Serum levels of 30 cytokines were measured by 30 Plex bead analysis (Luminex). NK cells were defined as CD3– CD56+. B cells were defined as CD3-CD19+. CD3+ CD4+.T-cell subsets were defined as CD45RO–CD27+ naïve, CD45RO+ CD27+ CD62L+ central memory, CD45RO+ CD27+ CD62L– effector memory, CD45RO+CD27– effectors and CD45RO– CD27– terminal effectors. DCs were defined based on their BDCA 1,2, 3 & CD16 expression. CD4 Tregs were defined as CD3+CD4+ CD25high CD27+Foxp3+. Treg subsets were defined as (1) CD45RA+CD25lo resting Tregs, (2) CD45RA-CD25hi activated Tregs, and (3) cytokine-secreting CD45RA-CD25lo non-Tregs1. Treg function was evaluated by cytokine secretion of T effector cells (Te) with and without Tregs. IFN-γ secreting CD4+ T-cells (Th1) were enriched by magnetic beads followed by FACS sorting. The clonality of Th1 cells was evaluated based on the diversity of T-cell receptors by spectratyping as well as sequencing. Transcription factor expression was measured by qPCR. Results: There were no significant differences in the number or percentage of different CD8 T-cells compared to healthy controls. Surprisingly, despite a borderline decrease in the absolute number of naïve (p=0.19) and central memory (p=0.20) CD4+T-cells the number and percentage of Tregs were no different from healthy controls (1.36×107/L v 1.34×107/L, p=0.57). Although the ratio of Tregs to CD4+ T-effectors (Te) was higher than in healthy controls, the difference was not significant (0.49 v 0.12, p=0.86). The absolute numbers and percentages of Th1 cells and TNF-α + CD4+ T-cells were significantly higher in AA patients compared to healthy controls (4.2 × 107/L v 0.9 × 107/L & 2.44 × 108 v 1.26 × 108(p=0.001, p=0.004)). The diversity of T-cell receptor on Th1 cells was significantly lower compared to healthy age matched controls (on average 21 & 52 peaks). Amongst AA patients, the numbers of Th2, Th17, NK and B cells were not significantly different from healthy controls, whereas the absolute numbers of all DCs were reduced(p<0.01). The serum levels of proliferative cytokines, EGF (p=0.01), HGF (p=0.01), VEGF (p=0.01) and pro-inflammatory cytokines IL-13 (p=0.02), IL-8 (p<0.001) were significantly higher in AA patients. The percentage of cytokine secreting CD4+ CD25+ T-cells was markedly decreased in AA patients and the activated Treg subsets were predominantly of CD45RA+ phenotype, which was significantly different from healthy controls. Sorted Tregs from AA patients were unable to suppress cytokine secretion by Te cells in a 1:1 co-culture. However, IL-2, IFN-γ and TNF-α secretion of Te from AA patients was suppressible by allogeneic Tregs from healthy controls (on average 11 time suppression), whereas Tregs from AA patients were unable to suppress healthy Te cells. However, dysfunctional Tregs were not associated with abnormality of transcription factors, as judged by the levels of STAT1, 3, 4, 5 & 6, FoxP3 & T-bet of Tregs that were not significantly different from healthy age matched controls. Conclusion: Our data show that although FoxP3+ Tregs are normal in AA, a subset of these cells is markedly reduced and the activated Tregs aberrantly express CD45RA. Furthermore, unlike normal Tregs, the Tregs from AA patients do not suppress the inflammatory cytokine secretion by Te cells. The absence of DCs in the peripheral blood suggests their immigration to the inflammation site (e.g. bone marrow), which may play a role in the polarisation of T helpers toward a Th1 phenotype. Clonal expansion of Th1 cells may suggest potential antigen specificity that may lead to AA phenotype. 1. Miyara M, et al. Immunity. 2009. Disclosures: No relevant conflicts of interest to declare.

scholarly journals CD28 Down-Regulation on CD4 T Cells Is a Marker for Graft Dysfunction in Lung Transplant Recipients

2008 ◽  
Vol 178 (7) ◽  
pp. 765-773 ◽  
Author(s):  
Sean M. Studer ◽  
M. Patricia George ◽  
Xuehai Zhu ◽  
Yifang Song ◽  
Vincent G. Valentine ◽  
...  
Keyword(s):  
T Cells ◽  
Cd4 T Cells ◽  
Lung Transplant ◽  
Transplant Recipients ◽  
Graft Dysfunction ◽  
Down Regulation ◽  
Lung Transplant Recipients

Anti-CD20 therapy corrects a CD8 regulatory T cell deficit in multiple sclerosis

2021 ◽  
pp. 135245852110033
Author(s):  
Quentin Howlett-Prieto ◽  
Xuan Feng ◽  
John F Kramer ◽  
Kevin J Kramer ◽  
Timothy W Houston ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
B Cell ◽  
Regulatory T Cell ◽  
Healthy Controls ◽  
Regulatory Cells ◽  
Long Term Treatment ◽  
Anti Cd20

Objective: To determine the effect of long-term anti-CD20 B-cell-depleting treatment on regulatory T cell immune subsets that are subnormal in untreated MS patients. Methods: 30 clinically stable MS patients, before and over 38 months of ocrelizumab treatment, were compared to 13 healthy controls, 29 therapy-naïve MS, 9 interferon-β-treated MS, 3 rituximab-treated MS, and 3 rituximab-treated patients with other autoimmune inflammatory diseases. CD8, CD28, CD4, and FOXP3 expression in peripheral blood mononuclear cells was quantitated with flow cytometry. Results: CD8+ CD28− regulatory cells rose from one-third of healthy control levels before ocrelizumab treatment (2.68% vs 7.98%), normalized by 12 months (13.5%), and rose to 2.4-fold above healthy controls after 18 months of ocrelizumab therapy (19.0%). CD4+ FOXP3+ regulatory cells were lower in MS than in healthy controls (7.98%) and showed slight long-term decreases with ocrelizumab. CD8+ CD28− and CD4+ FOXP3+ regulatory T cell percentages in IFN-β-treated MS patients were between those of untreated MS and healthy controls. Interpretation: Long-term treatment with ocrelizumab markedly enriches CD8+ CD28− regulatory T cells and corrects the low levels seen in MS before treatment, while slightly decreasing CD4+ FOXP3+ regulatory T cells. Homeostatic enrichment of regulatory CD8 T cells provides a mechanism, in addition to B cell depletion, for the benefits of anti-CD20 treatment in MS.

scholarly journals OP0287 A MACHINE LEARNING APPROACH FOR PRECISION STRATIFICATION OF JUVENILE-ONSET SLE

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 179.2-179
Author(s):  
G. Robinson ◽  
J. Peng ◽  
P. Dönnes ◽  
L. Coelewij ◽  
M. Naja ◽  
...  
Keyword(s):  
Machine Learning ◽  
Logistic Regression ◽  
T Cell ◽  
B Cell ◽  
T Cell Subsets ◽  
Healthy Controls ◽  
Juvenile Onset ◽  
Immune Signature ◽  
Immune Phenotyping ◽  
Over Time

Background:Juvenile-onset systemic lupus erythematosus (JSLE) is a complex and heterogeneous disease characterised by diagnosis and treatment delays. An unmet need exists to better characterise the immunological profile of JSLE patients and investigate its links with the disease trajectory over time.Objectives:A machine learning (ML) approach was applied to explore new diagnostic signatures for JSLE based on immune-phenotyping data and stratify patients by specific immune characteristics to investigate longitudinal clinical outcome.Methods:Immune-phenotyping of 28 T-cell, B-cell and myeloid-cell subsets in 67 age and sex-matched JSLE patients and 39 healthy controls (HCs) was performed by flow cytometry. A balanced random forest (BRF) ML predictive model was developed (10,000 decision trees). 10-fold cross validation, Sparse Partial Least Squares-Discriminant Analysis (sPLS-DA) and logistic regression was used to validate the model. Longitudinal clinical data were related to the immunological features identified by ML analysis.Results:The BRF-model discriminated JSLE patients from healthy controls with 91% prediction accuracy suggesting that JSLE patients could be distinguished from HCs with high confidence using immunological parameters. The top-ranked immunological features from the BRF-model were confirmed using sPLS-DA and logistic regression and included CD19+ unswitched memory B-cells, naïve B-cells, CD14+monocytes and total CD4+, CD8+and memory T-cell subsets.K-mean clustering was applied to stratify patients using the validated signature. Four groups were identified, each with a distinct immune and clinical profile. Notably, CD8+T-cell subsets were important in driving patient stratification while B-cell markers were similarly expressed across the JSLE cohort. JSLE patients with elevated effector memory CD8+T-cell frequencies had more persistently active disease over time, and this was associated with increased treatment burden and prevalence of lupus nephritis. Finally, network analysis identified specific clinical features associated with each of the top JSLE immune-signature variables.Conclusion:Using a combined ML approach, a distinct immune signature was identified that discriminated between JSLE patients and HCs and further stratified patients. This signature could have diagnostic and therapeutic implications. Further immunological association studies are warranted to develop data-driven personalised medicine approaches for JSLE.Acknowledgments:Lupus UK, Rosetrees Trust, Versus ArthritisDisclosure of Interests:George Robinson: None declared, Junjie Peng: None declared, Pierre Dönnes: None declared, Leda Coelewij: None declared, Meena Naja: None declared, Anna Radziszewska: None declared, Chris Wincup: None declared, Hannah Peckham: None declared, David Isenberg Consultant of: Study Investigator and Consultant to Genentech, Yiannis Ioannou: None declared, Ines Pineda Torra: None declared, Coziana Ciurtin Grant/research support from: Pfizer, Consultant of: Roche, Modern Biosciences, Elizabeth Jury: None declared

scholarly journals CRTAM determines the CD4+ cytotoxic T lymphocyte lineage

2015 ◽  
Vol 213 (1) ◽  
pp. 123-138 ◽  
Author(s):  
Arata Takeuchi ◽  
Mohamed El Sherif Gadelhaq Badr ◽  
Kosuke Miyauchi ◽  
Chitose Ishihara ◽  
Reiko Onishi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cytotoxic Activity ◽  
Cd4 T Cells ◽  
Intracellular Signaling ◽  
Ectopic Expression ◽  
T Cell Subsets ◽  
Naive T Cells ◽  
Naïve T Cells ◽  
Ifn Γ

Naive T cells differentiate into various effector T cells, including CD4+ helper T cell subsets and CD8+ cytotoxic T cells (CTL). Although cytotoxic CD4+ T cells (CD4+CTL) also develop from naive T cells, the mechanism of development is elusive. We found that a small fraction of CD4+ T cells that express class I–restricted T cell–associated molecule (CRTAM) upon activation possesses the characteristics of both CD4+ and CD8+ T cells. CRTAM+ CD4+ T cells secrete IFN-γ, express CTL-related genes, such as eomesodermin (Eomes), Granzyme B, and perforin, after cultivation, and exhibit cytotoxic function, suggesting that CRTAM+ T cells are the precursor of CD4+CTL. Indeed, ectopic expression of CRTAM in T cells induced the production of IFN-γ, expression of CTL-related genes, and cytotoxic activity. The induction of CD4+CTL and IFN-γ production requires CRTAM-mediated intracellular signaling. CRTAM+ T cells traffic to mucosal tissues and inflammatory sites and developed into CD4+CTL, which are involved in mediating protection against infection as well as inducing inflammatory response, depending on the circumstances, through IFN-γ secretion and cytotoxic activity. These results reveal that CRTAM is critical to instruct the differentiation of CD4+CTL through the induction of Eomes and CTL-related gene.

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