IMMUNOLOGY

Detailed explanation-1: -Helper T-cells aid other cells in the immune response. When they sense an infection, they release cytokines, molecules that send messages to other immune cells. These cytokines help activate cytotoxic T-cells to fight the infection.

Detailed explanation-2: -Cytotoxic T cells recognize antigen bound to MHC protein type 1. [2] MHC not only aid in T cell activation, but it also has a vital role in the maturation of T cells in the thymus.

Detailed explanation-3: -The central physiological function of the cytotoxic T lymphocyte (CTL) is to eliminate cells that express abnormal surface phenotype as a result of intrinsic changes within the cell. It would obviously be deleterious if, for instance, CTL are to destroy antigen processing cells essential for the antibody response.

Detailed explanation-4: -Cytotoxic T lymphocytes mediate lysis of target cells by various mechanisms, including exocytosis of lytic proteins (perforin, granzymes) and receptor-ligand binding of Fas/APO molecules.