Antigen-presenting macrophage activates helper T cell 1Phagocytosis of Bacterium the microbial Bacterial antigen invader 2 Antigens from the dismantled invader are attached to MHC 3MHC proteins and self proteins their attached antigens are displayed on macrophage MHC- surface Macrophage self protein Nucleus Lymphocyte (helper T cell) 4Helper T cells recognize antigens and MHC proteins and bind to the macrophage,initiating a series of immune events Antigen-presenting macrophage activates helper T cell