STUDIES ON CYTOPHILIC ANTIBODIES

Abstract

SummaryMarked physicochemical heterogeneity has been found previously among mouse antibodies eytophilic for macrophages. The possibility of heterogeneity among guinea‐pig cytophilic antibodies has also been noted. In the present study the susceptibility to proteolytic enzymes of the macrophage receptor sites for cytophilic antibodies has been investigated. Again important differences between two types of mouse cytophilic antibody have been seen, together with some differences between guinea‐pig and mouse cytophilic antibodies.Treatment of monolayers of guinea‐pig macrophages with papain does not abolish and may slightly increase their ability to be sensitized by homologous cytophilic antibodies. Similar treatment of guinea pig macrophages passively sensitized in vitro with cytophilic antibodies does not affect their ability to take up antigen (sheep erythrocytes). Treatment of mouse macrophages with trypsin or papain does not abolish and may slightly increase their ability to take up homologous cytophilic antibodies from hyperimmune sera. Similar treatment profoundly reduces their capacity to take up cytophilic antibodies from sera obtained early (7 days) after immunization with sheep erythrocytes in adjuvant. Treatment of mouse macrophages with serum after passive sensitization in vitro apparently removes all the cytophilic antibody taken up from early sera, but has much less effect on the cytophilic antibodies taken up from hyperimmune sera.