Suppressive Effects of CD4CD25 Regulatory T Cells on the Innate Immune Response
As described above, the investigation of the suppressive mechanism by Tregs showed that T cell suppression was mediated in a cell-contact-dependent manner. However, it was unclear whether this cell contact involved interac-tionsbetween TregsAPCorbetweenTregs andresponder Tcells. Inanelegant study Piccirillo and Shevach demonstrated that CD4 CD25 Tregs that were preactivated anti-with CD3 mAb and APC could suppress CD8 T cell proliferation and IFN-y production in response to stimulation with MHC...
Dendritic Cells Presenting HK ATPase
How autoreactive CD4 T cells become activated to initiate autoimmune disease is an actively investigated area of the pathophysiology of many autoimmune diseases. In the peripheral tissues, dendritic cells DCs sample the environment, acquiring self-antigens from tissue sites, perhaps by the phagocytosis of apoptotic cells Steinman et al. 2003 . These DCs migrate to the draining lymph nodes where they present the antigen in the context of MHC to specific T cells. It has recently been shown that...
Introduction Pqc
It is now approaching 10 years since the identification of a naturally occurring CD4 T cell with constitutive expression of CD25 IL-2Ra as a potent suppressor T cell population capable of controlling immune pathology Sak-aguchi et al. 1995 . Initial in vivo phenomena centered around their ability to suppress the induction of organ-specific autoimmune disease induced by day 3 thymectomy d3Tx of certain mouse strains Asano et al. 1996 Suri-Payer et al. 1998 or by transfer of autoeffector T cells...
Origin of Tregs Thymus and Peripheral Induction
A number of findings provide ample evidence that the majority of CD25 CD4 Tregs are produced within the thymus in the process of thymic selection as a functionally distinct and mature subpopulation of T cells. It is currently not known whether Tregs develop from a unique lineage precursor, or whether any CD4 CD8- thymocyte can differentiate into a Treg under particular conditions. In a normal thymus, 2 -5 of CD4 CD8- thymocytes express CD25, and these cells are functionally competent, as...
Promiscuous TissueAntigen Expression in TECs Selects Treg Repertoires The
In autoimmune repertoires, a most interesting question relates to the limited number of clinically identified AID. Thus, recessive tolerance models would predict as many distinct diseases as the number of autoreactive clones, or at least, as the number of autoantigens. The limitation in the range of clinical AID led Cohen to suggest that autoreactive repertoires would be focused onto a subset of autoantigens that he designated as immunological homunculus Cohen and Young 1991 . Evidence for...
Suppressive Effects of CD4CD25 Regulatory T Cells on the Adaptive Immune
It has been well established that CD4 CD25 Tregs can suppress the adaptive immune response by inhibiting CD4 and CD8 T cell proliferation and cytokine production 11, 22, 50-56 . CD4 CD25 Tregs can also inhibit au- toantibody production in vivo, although the direct suppressive effects on B cell immunoglobulin production in vitro have only been marginally investigated 57 . The mechanisms of suppression have mainly been studied in assays of T cell suppression. It has been shown by many groups that...
References Ycb
Abiola O, Angel JM, Avner P, Bachmanov AA, Belknap JK, Bennett B, Blankenhorn EP, Blizard DA, Bolivar V, Brockmann GA, Buck KJ, Bureau JF, Casley WL, Chesler EJ, Cheverud JM, Churchill GA, Cook M, Crabbe JC, Crusio WE, Darvasi A, de Haan G, Dermant P, Doerge RW, Elliot RW, Farber CR, Flaherty L, Flint J, Gershenfeld H, Gibson JP, Gu J , Gu W, Himmelbauer H , Hitzemann R , Hsu HC, Hunter K , Iraqi FF, Jansen RC, Johnson TE, Jones BC, Kempermann G, Lammert F, Lu L, Manly KF, Matthews DB, Medrano...
References Tdo
Albert LJ, Inman RD 1999 Molecular mimicry and autoimmunity. N Engl J Med 341 2068-2074 Almeida AR, Legrand N, Papiernik M, Freitas AA 2002 Homeostasis of peripheral CD4 T cells IL-2R alpha and IL-2 shape a population of regulatory cells that controls CD4 T cell numbers. J Immunol 169 4850-4860 Anastasi E, Campese AF, Bellavia D, Bulotta A, Balestri A, Pascucci M, Checquolo S, Gradini R, Lendahl U, Frati L, Gulino A, Di Mario U, Screpanti I 2003 Expression of activated Notch3 in transgenic mice...
Genetic Studies on Inbred Strains of Mice
Kojima and Prehn's study 1981 examining susceptibility to d3Tx-induced autoimmune disease in 21 different inbred and congenic strains of mice found strain variation in organ involvement, incidence, and severity of disease they also found that AIP was the only disease with a clear H2 association. However, H2-linkage has subsequently been extended to include susceptibility to both AOD and AIG Silveira et al. 2001 Roper et al. 2002 . Additional studies were carried out to address the inheritance...
Anergy of CD25 Suppressor T Cells An In Vitro Artifact
Based on the characterization of CD25 CD4 T cells in vitro, anergy was regarded as a hallmark of this class of T cells 31 . The general perception has been that conditions that break the anergy, i.e., co-stimulation or addition of high levels of exogenous IL-2 in the standard in vitro assay, would abolish suppression. Whether these in vitro characteristics actually represent the behavior of CD25 T cells upon antigen encounter in vivo remained elusive because of experimental limitations inherent...
The SCID Transfer Model of Colitis
In the transfer models of colitis, transfer of low numbers of CD4 T cells Claesson et al. 1996 or a subpopulation hereof from an immunocompetent syngeneic donor mouse to an immunodeficient animal SCID or RAG- - leads to chronic and lethal colitis in the recipient. In addition, transplantation of a full gut wall graft from a normal donor mouse into the skin of a histocom-patible SCID induces IBD Rudolphi et al. 1994 . While the original studies suggested that only adoptive transfer of sorted...
The Role of TCR Specificity in Naturally Arising CD25 CD4 Regulatory T Cell
C.-S. Hsieh1 K A. Y. Rudensky2 1 Department of Medicine, Division of Rheumatology, University of Washington, 2Howard Hughes Medical Institute and the Department of Immunology, University of Washington, Seattle, WA 98195, USA 25 26 3 Antigenic Specificity of Induced Regulatory T Cells 28 4 The Paradox of Foreign Antigen Recognition by Regulatory T Cells 30 5 Tr Appear to Have a Diverse TCR Repertoire That Is Different from the CD25- TCR Repertoire 33 6 A Large Proportion of Peripheral CD25 TCRs...
TNFa and Semimature DCs
The term immature is not accurately defined in many aspects and according to a long-standing definition true immature DCs are only found in peripheral tissues, whereas the impetus to migrate towards regional lymph nodes requires at least some activation. Indeed there are reports showing that lung-derived migratory DCs and hence partly activated DCs account for the induction of regulatory T cells 13 . Therefore tolerogenic DCs found in the lymph node may be differentially activated or...
Other Subsets of Regulatory T Cells Involved in the Control of Colitis
Many studies suggest that SCID mice with colitis lack Treg cells. In addition to the naturally occurring regulatory CD4 CD25 T cells, a number of different regulatory T cell populations, capable of inhibiting the response of other T cells, have been described Cottrez et al. 2000 Gad et al. 2003 Neurath et al. 1996 . Treg cells can be induced in vivo following oral exposure to antigen Th3 cells and in vitro after culture with antigen and IL-10 Tr1 cells or following co-culture of gut-derived CD4...
Regulatory T Cells as a Therapeutic Agent for Inflammatory Bowel Disease
As described above, regulatory CD4 CD45RBlow T cells enriched within the CD25 subsetaswellasTrl cellsandTregcellsfromDC CD4 Tcellco-culture have been shown to prevent the development of colitis induced by transfer of CD4 CD45RBhigh or CD4 CD25- T cells to SCID mice Foussat et al. 2003 Groux et al. 1997 Powrie et al. 1990,1993 M. Gad et al. submitted . Recently, different groups have tried to cure already established colitis with regulatory T cells in the SCID transfer model Foussat et al. 2003...
References Jvg
Annacker O, Pimenta-Araujo R, Burlen-Defranoux O, Barbosa TC, Cumano A, Ban-deira A 2001 CD25 CD4 T cells regulate the expansion of peripheral CD4 T cells through the production of IL-10. J Immunol 166 3008-3018 Annacker O, Malmstroem V, Bournbe T, Parker CM, Powrie F 2003 Essential role for CD103 in the T cell-mediated regulation of experimental colitis abstract . Immunology 110 117 Apostolou I, Sarukhan A, Klein L, von Boehmer H 2002 Origin of regulatory T cells with known specificity for...
The MM96 Solution to the Thymic Sorting of Emergent TCR Repertoires
The MM96 has solved these two problems, as it proposes that the highest subdeletional TCR self-affinities necessarily result in activation and com-mitmentofselectedcellsto theregulatorypathway. Thispostulate providesfor a double fail-safe mechanism to avoid pathogenic autoreactivity. On the one hand, the process of sorting the emergent TCR diversity includes the affinity-dependent selection of autoreactive Tregs, which conveniently isolates na ve T cell repertoires to well below autoreactivity...
RelB Translocation is Crucial for DC Maturation
Although most pharmaceuticals mentioned above have no structural similarities, it is most likely that their suppressive effects were mediated by the same mechanism, namely inhibition of maturation of DCs. On a molecular level, DC maturation is guided by relB, a subunit of the NFkB transcription factor. RelB has been shown to play a major role in DC function by regulating CD40 and MHC expression. Upon stimuli exerted by TNFa, LPS or virus-derived IL-1, relB translocates to the nucleus and...
Feedback Mechanisms Between Treg and DCs
Many results support the concept that DCs are inducers of Treg under certain circumstances. However, recent results imply that Treg, on the other hand, also affect DC functions 65 . For example, Misra et al. have shown that DC co-cultured with Treg remain in an immature state as judged by surface-marker expression 19 . These Treg-exposed DCs were inferior in induction of T cell proliferation and produced significant amounts of IL-10. In another murine cardiac transplantation model, increased...