CTLA4的免疫抑制作用机制 A Activation Inhibition by CTLA-4: competition for B7 MHC B7 tMe tMMN 竞争性结合B7 Peptide CD28 TCR CTLA-4 T cell Nucleus Activation Inhibition by CTLA-4 signaling block 抑制T细胞活化信号传导 CD28 CTLA-4 T cell Nucleus Abbas et al: Cellular and Molecular Immunology, Updated 6th EditionCTLA-4的免疫抑制作用机制 竞争性结合B7 抑制T细胞活化信号传导