[Extracorporeal immunosuppressive effect of papain]

Exposure of allogenic erythrocytes to papain induced their immunosuppressing properties within relatively narrow ranges of the incubation medium temperature (42 but not 37 or 40 degrees C) and the papain concentration (10 but not 2 or 50 micrograms/ml). Markedly pronounced immunosuppressing properties were acquired by the erythrocyte light fraction after heating and exposure to papain. The supernatant layer of adhesive spleen cells incubated in the presence of erythrocytes heat treated and exposed to papain suppressed development of the humoral immune response and DTH during the allogenic transfer and accelerated and increased excretion of the antigen specific immunosuppressing factor by the nonadhesive spleen cells of hyperimmunized sheep red blood cells.