8cel -Antigen 一CD40 Antigen presentation to helper T cell; expression of B7-2,B7-1 Helper T cell B7 CD28 Activation of T cell: expression of CD40 ligand, CD40 cytokine secretion ligand 某些抗原的抗体 Cytokines 产生仅需要细胞因子 B cell activation by CD40 ligand,cytokines B cell proliferation and differentiation (antibody secretion) 某些抗原的抗体 产生仅需要细胞因子