STUDIES ON CYTOPHILIC ANTIBODIES

An attempt was made to study the. dynamics of the interaction between cytophilie antibodies and the macrophage surface. Two aspects of the problem received particular attention: (1) the ability of macrophage cytophilic antibodies to sensitize (confer an affinity for antigen upon) cells of different species, and (2) the inhibitory effect of normal sera on homologous and heterologons sensitization.

Mouse and rabbit antibodies sensitized peritoneal macrophages from mouse, rabbit and guinea‐pig, although the cytophilic factor from “early” mouse serum did not sensitize guinea‐pig macrophages. Guinea‐pig antibodies sensitized guinea‐pig macrophages strongly, rabbit inacrophages weakly and inconsistently and mouse macrophages not at all.

Normal rabbit serum was inhibitory with all the combinations tested. Normal guinea‐pig serum was inhibitory with all combinations except mouse antibodies on rabbit macrophages. Normal mouse serum was inhibitory only when either the antibodies or the cells were from mice. Guinea‐pig niacrophages carrying cytophilic antibodies were desensitized by ineubation with normal guinea‐pig serum. Guinea‐pig macrophages carrying cytophilic antibodies to one antigen were as efficiently sensitized by cytophilic antibodies to another antigen as were normal guinea‐pig niacrophages. Normal human serum inhibited the uptake of guinea‐pig antibodies by guinea‐pig macrophages.