第三节 分子与信号转导水平的免疫调节 免疫细胞信号转导中的反馈调节 TCR TcR-CD3 complex CD3 CD3 The intracyt oplasmic re gion of the tcR chain is too short to transduce a signal. The CD3Y, 8, e or s chains are required for cell surface expression of the TcR-CD3 complex and signalling through the TcR ITAMs TKs Signalling is initiated by aggregation of adjacent TcR by MHCpe ptide antigen comple xes on APC Signalling is e ssential for clonal proli feration and differentiation to effector t cells, but alone is insufficient for full t cell act ivat ion第 三 节 分子与信号转导水平的免疫调节 一、免疫细胞信号转导中的反馈调节