第十章 T淋巴细胞(双语).pptVIP

第十章 T淋巴细胞(Section 10 T Lymphocytes) 第一节 T淋巴细胞的分化发育(Chapter 1 T Lymphocytes Ontogeny) Development of T lymphocytes In the Thymus Stages: double-negative(DN) stage; double-positive(DP) stage; single-positive(SP) stage. Location: thymic cortex→thymic medulla Events: generation of TCR; positive selection; negative selection. Results: expression of TCR, MHC restriction and self-immunological tolerance. Generation of TCR Location: in the thymic cortex. Stages: DN stage→DP stage Process: rearrangement of the TCRβgene first, expression of the pre-TCR( pTα-TCRβ) in DN stage; rearrangement of the TCRαgene, expression of anαβTCR in DP stage. Result: express functional TCRs, acquire high specificity. 第二节 T淋巴细胞的表面分子及其作用(Chapter 2 Surface Proteins of T Lymphocytes) Surface Proteins of T lymphocytes TCR-CD3复合物(TCR-CD3 complex) CD4分子和CD8分子(CD4 and CD8 coreceptors) 协同刺激分子(costimulatory molecules) 丝裂原结合分子(Mitogen receptors)及其他表面分子 一、TCR-CD3复合物 TCR-CD3 Complex TCR: a heterodimer composed either of a and b chains(95%-99%) or of g and d chains(1%-5%); abTCR specifically recognizes peptides bound to MHC molecules(MHC restriction). CD3: a complex of proteins(γε,δε,ζζorζη), transmits the first signal of T cell activation. 1、TCR（T cell receptor）的结构和功能 所有T细胞表面的特征性标志。 结构：TCR是由两条不同肽链构成的异二聚体，分别为?、?链（95%-99%）或?、?链（1%-5%），含V区和C区。 功能：识别抗原肽-MHC分子复合物。 2、CD3分子的结构和功能 结构：CD3分子有五种肽链，γ、δ、ε、ζ和η链，由三种二聚体组合而成（γε、δε、ζζ或ζη二聚体），通过盐桥与TCR形成稳定的复合物结构，其胞质区含有ITAM。 功能：转导TCR识别抗原所产生的活化信号。 CD4 and CD8 Coreceptors The mature T cells express either CD4 or CD8 molecule. CD4 and CD8 molecules are cell-surface proteins that increase the sensitivity of the antigen receptor to antigen by binding to associated ligands and participate in signal transduction. 二、CD4分子和CD8分子 成熟的T细胞只表达CD4或CD8分子。 主要功能是辅助TCR识别抗原和参与T细胞活化信号的传导，又称为T细胞的辅助受体。 CD4 Coreceptor Monomer; Expression: on 60％-65％ ofαβT cells and partial NKT cells; Functions: increases the sensitivity of the antigen receptor to antigen by binding toβ2 domain of MHC classⅡmo