ANTIBODY-ELICITING CAPACITY OF MACROPHAGES OBTAINED FROM SUCKLING RATS

Antibody-eliciting capacity of peritoneal macrophages obtained from the immunologically mature adult as well as immature, five-day-old, suckling rats was studied. Sheep red blood cells were used as the test antigen and the antibody-forming activity was assessed by the number of hemolytic plaque-forming cells per unit number of spleen cells or the hemagglutinin titer of the serum or both. It was shown that transplantation of the SRBC-containing macrophages derived from adult rats elicited the apparently normal antibody response in adult rats but not in the immunologically deficient suckling animals. It was also found that the macrophages of the suckling rats were capable of ingesting SRBC and of transferring the antibody-eliciting capacity when transplanted into normal adult rats after ingestion of the antigen. It was concluded from these results that maturation of the phagocytic as well as antigen-processing capacity of macrophages preceded the differentiation of immunologically competent, antigen-reactive cells or the precursor of antibody-forming cells or both.