T cells suppression

Fig. 4. Regulatory T-cell functions suppression of DCs that support the generation of effector T cells suppression of ThI, Th2, and ThI 7 cells suppression of allergen-specific IgE and induction of lgG4, IgA, or both suppression of mast cells, basophils, and eosinophils interaction with resident tissue cells and remodeling, and suppression of effectorT-cell migration to tissues. 

Regulatory T cells, or suppressor T cells, suppress the activation of an immune response. The activity of these cells in organ transplant is not well elucidated. 

Lacey SF, McDanal CB, Horuk R, Greenberg ML. The CXC chemokine stromal cell-derived factor 1 is not responsible for CD8+ T cell suppression of syncytia-inducing strains of HIV-1. Proc Natl Acad Sci U S A 1997 94(18) 9842-9847. 

Methotrexate Folic acid analog cancer chemotherapy, arthritis Inhibits proliferation T-cell suppression granulocytopenia lymphocytopenia... 

Tang Q, Henriksen KJ, Bi M, Finger EB, Szot G, Ye J, MasteUer EL, McDevitt H, Bonyhadi M, Bluestone JA In vitro-expanded antigen-specific regulatory T cells suppress autoimmune diabetes. J Exp Med 2004 199 1455-1465. 

Thornton AM. Shevach EM CD4+CD25+ immunoregulatory T cells suppress polyclonal T cell activation in vitro by inhibiting interleukin-2 production. J Exp Med 1998 188 287-296. 

Campbell C, McSharry C. Alexander J, LiewFY CD44-CD254- regulatory T cells suppress differentiation and functions of Thl and Th2 cells, Leishmania major infection, and colitis in mice. J Immunol 2003 170 394-399. 

Regulatory T Cells Suppress DC Maturation As outlined above, several lines of evidence indicate that DCs are crucially involved in the induction of Tregs. However, this interaction is not restricted to a DC-to-Treg one-way street, since several recent data revealed that Tregs in turn have an impact on DC development [11]. 

Ring S, Schafer SC, Mahnke K, Lehr HA, Enk AH CD4+ CD25+ regula- 41 tory T cells suppress contact hypersensitivity reactions by blocking influx of effector T cells into inflamed tissue. 

Smith J, et al Antigen-specific T cell suppression by human CD4+CD25+ regulatory T cells. Eur J Immunol 2002 32 1621-1630. 

Ling EM, Smith T, Nguyen XD, et al Relation of CD4+CD25+ regulatory T-cell suppression of allergen-driven T-cell activation to atopic status and expression of allergic disease. Lancet 2004 363 608-615. 

In addition to Thl cells, Treg cells are able to inhibit the development of allergic Th2 responses [47] and play a major role in allergen-SIT [41,42]. This review will examine allergen-specific peripheral tolerance mechanisms in humans and discuss novel ways of T-cell suppression. 

SCT includes autologous and allogeneic transplants and the choice is dependent on the end result desired as well as the risks and benefits of each procedure. Autologous transplants after immunoablative therapy function on the premise of T-cell suppression versus clonal deletion as a cause of tolerance induction in autoimmunity. 

Cyclophosphamide s major active metabolite is phosphoramide mustard, which cross-links DNA to prevent cell replication. It suppresses T-cell and -cell function by 30-40% T-cell suppression correlates with clinical response in the rheumatic diseases. Its pharmacokinetics and toxicities are discussed in Chapter 54. 

Marth T, Ring S, Schulte D, Klesch N, Strober W, Kelsall B, Stallmach A, Zeitz M Antigen-induced mucosal T cell activation is followed by Thl T cell suppression in continuously fed ovalbumin TCR-transgenic mice. Eur J Immunol 2000 30 3478-3486. 

In vivo information on cytotoxic T-cell-suppressing agents is very limited, but men and women have not been found to have sex-dependent differences in inhibition of lymphocyte proliferation, (129). Although numerous studies have postulated the presence of sex differences based on a higher incidence of organ rejection and increased mortality in women, it is not clear that these observations are due to sex differences (130). In an in vitro study, it was found that cyclosporine was metabolized faster by small intestinal microsomes from females, but this finding was based on only four female samples (131). 

BGprris J, Mizrahi T, Hauberr E, Shaked I, Shevach E, Schwartz M (2002b) Neuroprotective autoimmunity Naturally occunirrg CD4 + CD25 -I- regulatory T cells suppress the ability to withstand irrjury to the cerrtral rrervous system. Proc Natl Acad Sci USA 99 15620-15625. 

Figure 1.5 Modulation of the T cell-suppressive activity of PAMs by pre-exposure to GM-CSF TNF. Data shown are the proliferative responses of lymph node cells (LNC) to mitogen in the presence of PAMs at a concentration equivalent to of the bold cells in culture the PAMs were pretreated for 48 h with medium alone, or medium supplemented with the cytokines shown. Untreated PAMs exhibited suppressive activity comparable to the medium-treated group. Reproduced with permission from Bilyk and Holt (1993).

From these data it might be expected that removal of CD8 T cells would enhance IgE production and favour TH2-type immune responses. However, this appears to depend on the stage at which depletion is carried out. Thus, if CD8 T cells are depleted in rats (using the mAb OX-8) in which an IgE response had been induced, then the usual decline in serum IgE levels is prevented (Holmes etal., 1994). This supports the view that CD8 T cells suppress IgE. However, if depletion of CD8 T cells is performed prior to immunization, then the IgE response is not enhanced. Moreover, the IgE response is... 

Transforming growth factor-/ (TGF-/ ) TGF- Lymphocytes Macs B cells suppresses growth inhibits IgM and IgG production decreases MHC II expression T cells suppresses growth Monocytes inhibits TNF production chemotaxis induces IL-1 and IL-6 expression... 

N. A. Gomes, J. O. Previato, B. Zingales, L. Mendonga-Previato, and G. A. DosReis, Down-regulation of T lymphocyte activation in vitro and in vivo induced by glycoinositolphospholipids from Trypanosoma cruzi. Assignment of the T cell-suppressive determinant to the ceramide domain, J. Immunol., 156 (1996) 628-635. 

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