Understanding of Immune Escape Mechanisms and Advances in Cancer Immunotherapy

Figure 1

Mechanism of T cells in immunomodulation in cancer therapy. (a) T cells activate the first signal: CD4⁺ T cells bind to MHC-I signal carrying tumor antigen, and CD8⁺ T cells bind to MHC-I signal carrying tumor antigen; T cells activate the second signal: CD28 molecule binds to B7 on the surface of antigen-presenting cells. (b) CD4⁺ T cells, as helper T cells, enhance the antitumor effect mainly by stimulating the activation of CD8⁺ T cells; as cytotoxic cells, CD8⁺ T cells kill tumor cells mainly through Fas/FasL pathway and granule exocytosis pathway.