上商充通大￥ Shanghai Jiao Tong University antibody CD40 ligand Interaction between secretion 3.Interactions between 4.Activated helper T cell the TH2 cell and B proteins on the proliferates into cytokine release cell causes the B antigens macrophage and helper either TH1 or TH2 cells, cellto proliferate T cell occur,activating which secrete different CD40 differentiate,and the helper T cell. types of cytokines. produce antibodies. 2.Macrophage presents Humoral immune a fragment of the activated response activated antigen on its surface. helper T cell. B cell antibody-producing TH2 cell plasma cell class II MHC B-cell receptor (mature B cel1) protein presenting class II MHC antigen 1.Macrophage antigen fragment Cell-mediated protein presenting captures, immune response antigen fragment antigens engulfs,and helper T-cell digests T cell receptors Cutokines secreted an antigen. by the TH1 cell class I MHC protein activate cytotoxic presenting antigen CD28 TH1 cell T cells to kill the fragment Cell infected infected target cell. with antigen B7 cytokine presents antigen D。1·0 release● fragments on its 。。 surface. cytotoxic T cell Activated cytotoxic T cell Cytokines secreted by the TH1 proliferates and differentiates into a mature cytotoxic T cell, macrophage cell stimulate the macrophage which binds to an infected to destroy ingested antigens target cell and initiates the more efficiently destruction of that cell. 1999 Encuclopaedia Britannica,Inc. mature cytotoxic T cellShanghai Jiao Tong University