Macrophage phagocytic recognition sites. Demonstration of selectivity by hetero- and alloantisera

Separate and independent phagocytic recognition sites have been identified on mouse peritoneal macrophages through the use of xenogeneic antimacrophage serum (AMS) and allogeneic anti H-2 antisera. Anti H-2d and anti H-2b antisera inhibit the binding and ingestion of opsonized erythrocytes (EA) by macrophages bearing H-2 haplotypes d and b, respectively. AMS and its F(ab')2 and Fab fragments inhibit the binding and ingestion of EA, and the ingestion but not the binding of 125I-labelled Shigella by macrophages. Neither antiserum inhibited the binding or ingestion of latex particles by macrophages. The results suggest that particulate binding to macrophages can be inhibited by two different mechanisms: a non-specific one where antibody bound to certain cell-surface antigens can mediate either directly or indirectly, and a specific interaction with Fc receptors. The possible mechanisms of non-specific antibody mediated phagocytic inhibition are discussed.