Max-Plan&-I nstitut fur I mmunbiologie, Frei bu rg/Bng.
Antibody-mediated target cell lysis by non-immune cells. Characterization of the antibody and effector cell populationsCells from normal rabbit thymus, lymph node and spleen demonstrated in vitro cytolytic activity when incubated with antibody-coated target cells. High dilutions of antibody were effective, and the degree of lysis was dependent on the lymphocyte-target cell ratio, In the spleen, two populations of effector cells were defined -one population consisted of phagocytic cells which were responsible for the onset of initial rapid lysis. A second population of cells, lymphocytes, were responsible for lysis, which proceeded at a slower, but continuous rate. Purified lymph node and thymus cells contained only the latter population. Both effector cell populations required the presence of an intact Fc piece on the target cell-bound antibody molecule for lysis t o proceed. Antibody-mediated lymphocyte cytotoxicity appeared to be specific and required cell-to-cell contact.