In Vivo Localization of Heterologous Anti-Erythrocyte Antibodies in the Rat Bone Marrow and Their Effect on the Proliferative Capacity of Immature Erythroid Cells

The in vivo localization of heterologous anti-erythrocyte antibodies in the rat bone marrow was determined by the I¹³¹-labeled antibody technic. I¹³¹-labeled anti-erythrocyte antibodies localized specifically in the bone marrow indicating the presence of localizing antibody. Both the localizing antibody and the incomplete antibody were thermostable, whereas hemolysins and hemagglutinins were thermolabile. Following an intravenous injection of antierythrocyte antibodies in rats, hemolysins and hemagglutinins were cleared rapidly from the plasma. The incomplete antibodies became attached to circulating red cells within 6 hours and red cell sensitization persisted for 1 week. The localizing antibody localized in the bone marrow within 30 minutes, leaving no activity in plasma.

The anti-erythrocyte antibodies markedly reduced the uptake of tritiated thymidine by erythroblasts in vitro, demonstrating their inhibitory effect on the proliferative capacity of erythroblasts.