摘要未致敏T细胞的活化至少需要两种信号,只有在两种信号同时存在时,T细胞才能有效活化、增殖,进而分泌细胞因子或发挥细胞毒性作用.第一信号由T细胞受体识别抗原产生,经CD3分子将信号传导至细胞内；第二信号是非抗原依赖性的“协同刺激信号”,它是由抗原呈递细胞或靶细胞表面的协同刺激分子与T细胞表面的协同刺激分子受体相互作用而提供的.这些协同刺激分子中最重要的是抗原呈递细胞表面的B7分子和T细胞表面的CD28、细胞毒T细胞抗原-4.

abstractsTcells need two signals to promote their activation.Only two signals existing at the same time,T cells can effectively activate,proliferate and secrete cell factors or play the toxic effects of cells.One signal is that T cell receptor recognize antigen and CD3 will transduce it to cells.The other is the combination of costimulatory molecules from antigen-presenting cell and costimulatory molecules receptor on the T cell surface.B7 on antigen-presenting cell and CD28/cytotoxic T lymphocyte-antigen-4 expressed on T cells are the most important costimulatory molecules.