Effect of Antimacrophage Serum on Antibody Production and Phagocytosis in Mice

Abstract

Abstract During the last year four reports have appeared in the literature on the effect of antimacrophage serum (AMS) on phagocytosis and antibody production (1–4). There is general agreement that AMS is cytotoxic to macrophages (1–4) and can decrease the phagocytic activity of peritoneal macrophages (1–4), but some investigators find no immunosuppressive effects after AMS treatment (1, 3), and others (2) report immunosuppression only under certain conditions of antigen administration. In this report we present evidence that AMS, which decreases the phagocytic activity of mouse peritoneal macrophages, also inhibits primary antibody synthesis. The immunosuppressive effect, however, can only be detected after pretreatment with AMS and low doses of antigen. Rabbit anti-mouse macrophage serum (AMS) was prepared by injecting New Zealand rabbits three times at bi-weekly intervals, i.v., with 108 or 109 peritoneal cells from C3H/HeJ donor mice. Peritoneal cell donors were injected 7 days previously with 3 ml of thioglycollate medium (5).