Mechanism of Rapid Tumor Lysis by Human ADCC: Mediation by Monoclonal Antibodies and Fragmentation of Target Cell DNA
Immunologically programmed cell destruction is an important defense mechanism for limiting the spread of invasive intracellular parasites and malignant cells in the body (1,2). However, when such processes are misdirected, in autoimmune diseases for example, they can be very harmful to normal tissues and can interfere with vital tissue functions (2). Thus, it is of considerable value to understand the mechanisms of cytolytically induced cell destruction as mediated by the immune system. Several such mechanisms have evolved with the immune system of man, and each is characterized by distinct antigen recognition requirements and/or distinct lytic processes. Some cytolytic mechanisms require only the secreted products of cells and not the direct intervention of an effector cell for cytolysis to occur, as with complement plus antibody-mediated cytotoxicity (CAMC), for example. Other mechanisms, however, do require that intimate contact be made between an effector cell and its target cell. Various lymphocytes, such as cytotoxic T lymphocytes (CTL), natural killer (NK) cells, and killer (K) cells all appear to initiate the lytic process only after contact is made with the target cell (1–4).
KeywordsNatural Killer Target Cell Effector Cell K562 Cell Mixed Lymphocyte Culture
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