scholarly journals Cooperative Roles of CTLA-4 and Regulatory T Cells in Tolerance to an Islet Cell Antigen

2004 ◽  
Vol 199 (12) ◽  
pp. 1725-1730 ◽  
Author(s):  
Mark P. Eggena ◽  
Lucy S.K. Walker ◽  
Vijaya Nagabhushanam ◽  
Luke Barron ◽  
Anna Chodos ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Immune Responses ◽  
Islet Cells ◽  
Pancreatic Islet Cells ◽  
Regulatory Cells ◽  
Wild Type ◽  
Activation Threshold ◽  
Islet Antigen ◽  
Self Antigen

Adoptive transfer of ovalbumin (OVA)-specific T cells from the DO.11 TCR transgenic mouse on a Rag−/− background into mice expressing OVA in pancreatic islet cells induces acute insulitis and diabetes only if endogenous lymphocytes, including regulatory T cells, are removed. When wild-type OVA-specific/Rag−/− T cells, which are all CD25−, are transferred into islet antigen–expressing mice, peripheral immunization with OVA in adjuvant is needed to induce diabetes. In contrast, naive CTLA-4−/−/Rag−/− OVA-specific T cells (also CD25−) develop into Th1 effectors and induce disease upon recognition of the self-antigen alone. These results suggest that CTLA-4 functions to increase the activation threshold of autoreactive T cells, because in its absence self-antigen is sufficient to trigger autoimmunity without peripheral immunization. Further, CTLA-4 and regulatory T cells act cooperatively to maintain tolerance, indicating that the function of CTLA-4 is independent of regulatory cells, and deficiency of both is required to induce pathologic immune responses against the islet self-antigen.

scholarly journals The tolerogenic interplay(s) among HLA-G, myeloid APCs, and regulatory cells

Blood ◽  
2011 ◽  
Vol 118 (25) ◽  
pp. 6499-6505 ◽  
Author(s):  
Edgardo D. Carosella ◽  
Silvia Gregori ◽  
Joel LeMaoult
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Immune Responses ◽  
Recent Work ◽  
Large Body ◽  
Regulatory Cells ◽  
Individual Effects ◽  
The Individual ◽  
Key Aspects ◽  
Antigen Presenting

Abstract Myeloid antigen-presenting cells (APCs), regulatory cells, and the HLA-G molecule are involved in modulating immune responses and promoting tolerance. APCs are known to induce regulatory cells and to express HLA-G as well as 2 of its receptors; regulatory T cells can express and act through HLA-G; and HLA-G has been directly involved in the generation of regulatory cells. Thus, interplay(s) among HLA-G, APCs, and regulatory cells can be easily envisaged. However, despite a large body of evidence on the tolerogenic properties of HLA-G, APCs, and regulatory cells, little is known on how these tolerogenic players cooperate. In this review, we first focus on key aspects of the individual relationships between HLA-G, myeloid APCs, and regulatory cells. In its second part, we highlight recent work that gathers individual effects and demonstrates how intertwined the HLA-G/myeloid APCs/regulatory cell relationship is.

scholarly journals Regulation of Intrinsic and Bystander T Follicular Helper Cell Differentiation and Autoimmunity by Tsc1

2021 ◽  
Vol 12 ◽  
Author(s):  
Shimeng Zhang ◽  
Lei Li ◽  
Danli Xie ◽  
Srija Reddy ◽  
John W. Sleasman ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Differentiation ◽  
Immune Responses ◽  
B Cell ◽  
Regulatory Cells ◽  
Wild Type ◽  
Autoantibody Production ◽  
Cell Responses ◽  
Tfh Cells ◽  
Follicular Helper

T Follicular helper (Tfh) cells promote germinal center (GC) B cell responses to develop effective humoral immunity against pathogens. However, dysregulated Tfh cells can also trigger autoantibody production and the development of autoimmune diseases. We report here that Tsc1, a regulator for mTOR signaling, plays differential roles in Tfh cell/GC B cell responses in the steady state and in immune responses to antigen immunization. In the steady state, Tsc1 in T cells intrinsically suppresses spontaneous GC-Tfh cell differentiation and subsequent GC-B cell formation and autoantibody production. In immune responses to antigen immunization, Tsc1 in T cells is required for efficient GC-Tfh cell expansion, GC-B cell induction, and antigen-specific antibody responses, at least in part via promoting GC-Tfh cell mitochondrial integrity and survival. Interestingly, in mixed bone marrow chimeric mice reconstituted with both wild-type and T cell-specific Tsc1-deficient bone marrow cells, Tsc1 deficiency leads to enhanced GC-Tfh cell differentiation of wild-type CD4 T cells and increased accumulation of wild-type T regulatory cells and T follicular regulatory cells. Such bystander GC-Tfh cell differentiation suggests a potential mechanism that could trigger self-reactive GC-Tfh cell/GC responses and autoimmunity via neighboring GC-Tfh cells.

scholarly journals CCR7 is required for the in vivo function of CD4+ CD25+ regulatory T cells

2007 ◽  
Vol 204 (4) ◽  
pp. 735-745 ◽  
Author(s):  
Martin A. Schneider ◽  
Josef G. Meingassner ◽  
Martin Lipp ◽  
Henrietta D. Moore ◽  
Antal Rot
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Immune Responses ◽  
Wild Type ◽  
Immunodeficient Mice ◽  
Cognate Antigen ◽  
Inflammatory Bowel ◽  
Secondary Lymphoid Organs

CCR7-mediated migration of naive T cells into the secondary lymphoid organs is a prerequisite for their encounter with mature dendritic cells, the productive presentation of cognate antigen, and consequent T cell proliferation and effector differentiation. Therefore, CCR7 was suggested to play an important role in the initiation of adaptive immune responses. In this study, we show that primary immunity can also develop in the absence of CCR7. Moreover, CCR7-deficient knockout (KO) mice display augmented immune responses. Our data cumulatively suggest that enhanced immunity in CCR7 KO mice is caused by the defective lymph node (LN) positioning of FoxP3+ CD4+ CD25+ regulatory T cells (T reg cells) and the consequent impediment of their function. The FoxP3+ T reg cells express CCR7 and, after their adoptive transfer, migrate into the LNs of wild-type mice. Here, they proliferate in situ upon antigen stimulation and inhibit the generation of antigen-specific T cells. Conversely, transferred CCR7-deficient T reg cells fail to migrate into the LNs and suppress antigen-induced T cell responses. The transfer of combinations of naive and T reg cells from wild-type and CCR7 KO mice into syngeneic severe combined immunodeficient mice directly demonstrates that CCR7-deficient T reg cells are less effective than their wild-type counterparts in preventing the development of inflammatory bowel disease.

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 A role for CD9 molecules in T cell activation.

1996 ◽  
Vol 184 (2) ◽  
pp. 753-758 ◽  
Author(s):  
X G Tai ◽  
Y Yashiro ◽  
R Abe ◽  
K Toyooka ◽  
C R Wood ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
T Cell Activation ◽  
Cell Activation ◽  
Expression Cloning ◽  
Wild Type ◽  
Almost All ◽  
Antigen Presenting ◽  
Deficient Mice

Costimulation mediated by the CD28 molecule plays an important role in optimal activation of T cells. However, CD28-deficient mice can mount effective T cell-dependent immune responses, suggesting the existence of other costimulatory systems. In a search for other costimulatory molecules on T cells, we have developed a monoclonal antibody (mAb) that can costimulate T cells in the absence of antigen-presenting cells (APC). The molecule recognized by this mAb, 9D3, was found to be expressed on almost all mature T cells and to be a protein of approximately 24 kD molecular mass. By expression cloning, this molecule was identified as CD9, 9D3 (anti-CD9) synergized with suboptimal doses of anti-CD3 mAb in inducing proliferation by virgin T cells. Costimulation was induced by independent ligation of CD3 and CD9, suggesting that colocalization of these two molecules is not required for T cell activation. The costimulation by anti-CD9 was as potent as that by anti-CD28. Moreover, anti-CD9 costimulated in a CD28-independent way because anti-CD9 equally costimulated T cells from the CD28-deficient as well as wild-type mice. Thus, these results indicate that CD9 serves as a molecule on T cells that can deliver a potent CD28-independent costimulatory signal.

scholarly journals TGF-β3-expressing CD4+CD25−LAG3+ regulatory T cells control humoral immune responses

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Tomohisa Okamura ◽  
Shuji Sumitomo ◽  
Kaoru Morita ◽  
Yukiko Iwasaki ◽  
Mariko Inoue ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Immune Responses ◽  
Humoral Immune ◽  
Humoral Immune Responses

Mesenchymal stem cells induce the expansion of regulatory T cells in abortion-prone mice

Reproduction ◽  
2021 ◽  
Author(s):  
Amir Salek Farrokhi ◽  
Amir-Hassan Zarnani ◽  
Fatemeh Rezaei kahmini ◽  
Seyed Mohammad Moazzeni
Keyword(s):  
Stem Cells ◽  
T Cells ◽  
Mesenchymal Stem Cells ◽  
Regulatory T Cells ◽  
Immune Responses ◽  
Lymph Nodes ◽  
De Novo ◽  
Abortion Rate ◽  
Cellular Mechanisms ◽  
Inguinal Lymph Nodes

Recurrent pregnancy loss (RPL) is one of the most common complications of early pregnancy associated in most cases with local or systemic immune abnormalities such as the diminished proportion of regulatory T cells (Tregs). Mesenchymal stem cells (MSCs) have been shown to modulate immune responses by de novo induction and expansion of Tregs. In this study, we analyzed the molecular and cellular mechanisms involved in Treg-associated pregnancy protection following MSCs administration in an abortion-prone mouse mating. In a case-control study, syngeneic abdominal fat-derived MSCs were administered intraperitoneally (i.p) to the DBA/2-mated CBA/J female mice on day 4.5 of pregnancy. Abortion rate, Tregs proportion in spleen and inguinal lymph nodes, and Ho1, Foxp3, Pd1, and Ctla4 genes expression at the feto-maternal interface were then measured on day 13.5 of pregnancy using flow cytometry and quantitative RT- PCR, respectively. The abortion rate in MSCs-treated mice was significantly reduced and normalized to the level observed in normal pregnant animals. We demonstrated a significant induction of Tregs in inguinal lymph nodes but not in the spleen following MSCs administration. Administration of MSCs remarkably upregulated the expression of HO1, Foxp3, Pd1, and Ctla4 genes in both placenta and decidua. Here, we show that MSCs therapy could protect the fetus in the abortion-prone mice through Tregs expansion and up-regulation of Treg-related genes. These events could establish an immune-privileged microenvironment, which participates in regulation of detrimental maternal immune responses against the semi-allogeneic fetus.

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