免疫调节_陈建忠.ppt.ppt

* 发挥调节作用的Th1和Th2亚群在功能上的相互拮抗 Th1和Th2亚群各自藉助分泌的细胞因子和激活的亚群专一性转录因子以调节性T细胞的形式抑制另一亚群的分化 * * * IFN-?逆转Th2极化格局通过激活Th1诱导抗胞内菌免疫 * 2 * D. Regulation by idiotypes and anti-idiotypic antibodies Antibodies formed against Ag-binding sites of an Ab are called anti-idiotypic antibodies, and are capable of influencing the outcome of an immune response. Id and AId interactions may enhance or suppress Ab responses. * Isotype The genes for isotype variants are present in all healthy member of a species. * (2) Allotype This refers to genetic variation between individuals within a species. * (3) Idiotype Variation in the V domain ,particularly in CDR, produces idiotype. * * Idiotype network and antigen internal image Ag Ag Ab1 (Id) Ab2 (AId) Ab3 Ab ? ? epitope * 利用独特型网络进行免疫干预的两种主要途径 Ag Ab2? 增强Ab1 Ab1 Ab2 B A Ab3 / Ab1 Ab1 Ab2? Ab2? 削弱Ab1 * E. Regulation by apoptosis 1. Activation-induced cell death (AICD) Fas (CD95) and FasL Fas membrane protein is expressed on lymphoid and other cells but is increased in expression with cellular activation. FasL is expressed on activated T cells. Thus, activation of T cells results in the expression of both Fas and FasL. The intracellular portion of the Fas receptor molecule contains ‘death domains’, which recruit proteins that lead to the activation of a cascade of proteases which induce apoptosis. Fas-FasL interaction is a major means of mediating AICD in CD4+ T cell. * (1) Fas/FasL and death signal transduction  evoked by Fas molecules DD: death domain 70 aa 80 aa 150 aa FasL Fas (receptor) Fas (CD95), a type I membrane protein with 325 aa (48 kD) FasL (Fas ligand), a type II membrane protein with 235 aa sFasL * Fas-FasL pathway Caspase:胱天蛋白酶 * * Major advances have recently been made in mapping the loci which govern susceptibility to the autoimmune disease. When the lymphoproliferative (lpr) gene is present in mouse strains, it causes the development