The Production of Erythrocyte Autoantibodies in Chimpanzees

Young adult chimpanzees immunized with human blood products produced circulating antibodies which reacted with human red cells of a certain proportion of chimpanzees. In addition, agglutinins were formed which reacted with the animals' own erythrocytes. That these agglutinins were true autoantibodies was demonstrated by: (a) their ability to sensitize the animals' own erythrocytes at 37 degrees C both in vivo and in intro; (b) the iso-specificity which they displayed toward other chimpanzee red cells; and (c) the fact that they belonged to the gamma(G)-class of immunoglobulins. Complement appeared to be bound to the in vivo sensitized cells but no evidence of increased cell destruction was observed. It seemed most likely that these autoagglutinins were produced as a result of active immunization with closely related antigens.