[Immunodepressive effect of cell populations with varying erythropoietic activity in embryos and newborn mice]

The cells of liver from the 11-12 day old embryos and of spleen from newborn mice were transplanted to adult syngeneic recipients immunized by the ram erythrocytes. The immune response in the recipient spleens was estimated by the number of antibody-forming cells. The cells of embryonic liver and of newborn spleen suppressed the immune response in recipients to a great extent. The immunodepressive effect obtained was similar to suppression due to the transfer of cell populations from the mice in which erythropoiesis was stimulated by hypoxia of phenylhydrazine. The splenocytes of adult control mice and the cells of spleen from 6-9 day old mice did not exert such an effect. The rabbit antiserum to erythroid cells relieved the suppressor effect of the embryonic liver and neonatal spleen cells, as well as of the other erythropoietic populations. A conclusion is drawn on participation of cells-suppressors of the erythroid nature in the mechanisms of immunological non-responsiveness at the early ontogenetic stages in mice.