Assays of Cell-Mediated Immunity
Cell-mediated immunity is the second arm of specific immune responses. Cell-mediated immunity is evoked by T lymphocytes, but macrophages and to a lesser extent polymorphonuclear leukocytes also play a role in these reactions. The main manifestations of cellmediated immunity are delayed type hypersensitivity, organ transplant rejection, tumour immunity, and resistance to a variety of infectious pathogens, such as parasites and intracellular bacteria. The most recent trend in immunological research gave much emphasis on this aspect of immune responsiveness. Available models to explore cellmediated immunity include in vivo tests, such as delayed-type hypersensitivity, and to a much lesser extent in the context of immunotoxicity evaluation, allograft rejection and graft-versus-host reaction, and in vitro or ex-vivo tests, such as lymphocyte proliferative responses and more recently cytokine production (Luster et al., 1982).