Immunology APCs

The generation of peripheral Treg cells may result in the establishment of homeostasis after its disruption. Examples include infection, autoimmune diseases, certain forms of cancers and immunodeficiency syndrome. The mechanisms by which peripheral Treg cells induce self-tolerance and homeostasis may involve cytokines or cell-cell interaction. The cytokines IL-10 and TGF-(3 and molecules such as CTLA-4 are involved in the effector mechanisms of Treg cells. The indirect effects of Treg cells may be mediated via APCs or NK cells. More specifically, the assembly of immunological synapse between APCs and effector cells is modulated by Treg cells, which may be mediated via direct or indirect mechanisms. 

Hiltbold, E.M., Poloso, N.J. and Roche, PA. (2003) MHC class Il-peptide complexes and APC lipid rafts accumulate at the immunological synapse. J. Immunol. 170, 1329-1338. 

Sometimes, as with sulfamethoxazole, the drug itself does not react with proteins or peptides to induce an immune response. Rather, intracellular metabolism of the parent drug forms the metabolite, sulfamethoxazole-nitroso, which binds covalently to proteins and peptides and induces immunogenicity [41]. This represents a drug that is a pro-hapten, which is immunologically reactive and able to bind to MHC complexes on APCs only after it is metabohzed. 

When stimulated by antigens, T cells secrete soluble factors that can be cytotoxic or ceU-stimulatory.Tohelp ensure thatb) tander ceUs are not affected, factor sea-etion is directed toward the immunological synapse , the junction between the T cdl and the antigen-presenting cell (APC). Directional secretion is mediated by the polarization of... 

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