cellular immunity [L, cellula, little cell, immunis, exempt] , the mechanism of acquired immunity characterized by the dominant role of T cell lymphocytes. Cellular immunity is involved in resistance to infectious diseases caused by viruses and some bacteria and in delayed hypersensitivity reactions, some aspects of resistance to cancer, certain autoimmune diseases, graft rejection, and certain allergies. It does not involve the production of humoral antibody but instead involves the activation of Mo and natural killer cells. Also called cell-mediated immunity. Compare humoral immunity.
