Natural cell-mediated cytotoxicity in rats. I. Tissue and strain distribution, and demonstration of a membrance receptor for the Fc portion of IgG.

Studies in mice and in humans have provided most of the available information concerning natural cell-mediated cytotoxicity. Rats represent a second experimental species which is well suited for the study of natural cytotoxicity. Our studies indicate that the distribution of natural killer (NK)3 cells in rat lymphoid tissues is similar to their tissue distribution in man, with high levels in the blood and spleen and low or undetectable levels in lymph node, thymus, thoracic duct or peritoneal exudate cells. The levels of NK activity varied considerably among various inbred strains of rats. However, the genetic control of levels of NK activity did not appear to be linked to the rat major histocompatibility complex. As recently demonstrated in mice by depletion experiments on antibody-erythrocyte monolayers, many or most rat natural killer cells were found to have surface receptors for the Fc portion of IgG.