Mechanisms of rejection by presentation of graft antigens to lymphocytes. Top right, silhouette of a man with a kidney transplanted into his right iliac fossa. The antigen presenting cell (CPA) (in pink, in the center and in the magnifying glass on the lower left) will present the graft antigen to the T8 (dark blue nucleus) and T4 (medium blue nucleus) lymphocytes. The T4 lymphocyte will produce interleukins (IL2, IL6) which will in turn stimulate the production of antibodies via the B cell (purple nucleus) and NK macrophage cells (green core). The T8 lymphocyte will be cytotoxic and cause lysis of the graft cells. The magnifying glass at the bottom left details the presentation of the graft antigen and the different receptors CD 3 (yellow), CD4 (white), CD28 (green) and CD40 (orange) in connection with CPA.