|Cell-mediated immunity is an immune response that does not involve antibodies but rather engages the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the issue of diverse cytokines in response to an antigen. Cellular immunity defends the body by: triggering antigen-specific cytotoxic T-lymphocytes that are able to induce apoptosis in the body cells displaying epitopes of the foreign antigen on their surface, such as cells with intracellular pathogens, virus-infected cells and cancer cells displaying tumor antigens; triggering macrophages and natural killer cells, enabling to destroy pathogens; and therefore stimulating cells to secrete a kind of cytokines that influence the function of other cells engaged in adaptive immune answers and innate immune answers. Cell-mediated immunity is administered primarily at microbes that survive in phagocytes and microbes that contaminate non-phagocytic units. It is also most effective in removing virus-infected cells, but also takes part in keeping defending against intracellular bacteria, protozoans, fungi and cancers. It also performances a foremost function in transplant rejection. The role of effector T cells in cell-mediated and humoral immune answers to agent pathogens. Cell-mediated immune answers engage the destruction of infected units by cytotoxic T units, or the destruction of intracellular pathogens by macrophages. The activation of naive T units in answer to antigen, and their subsequent expansion and differentiation, constitutes a prime immune response.