Counts of stromal precursor cells in heterotropic bone marrow transplants in mice immunized with group A streptococcus antigens

The count of stromal precursor cells in bone marrow transplants from CBA mice, transplanted to animals immunized with killed type 5 group A streptococcus vaccine, decreased 4.5-6.5 times (depending on the transplant age) in comparison with the grafts transplanted to normal recipients. The counts of stromal precursor cells in 1.5-3-month bone marrow transplants from animals immunized with killed streptococcal vaccine transplanted to normal mice were virtually the same, while in 7-month transplants they decreased 2-fold in comparison with their counts in bone marrow transplants from normal CBA mice transplanted to normal animals. The content of stromal precursor cells in the femoral bone marrow of animals immunized with killed streptococcal vaccine was appreciably (3.5 times) higher than in the bone marrow of normal mice. The results attest to an appreciable effect of streptococcal antigens on the bone marrow stromal tissue and suggest that not all stromal precursor cells, whose count increases after injection of antigens, are responsible for transplantability of the stromal tissue in case of its heterotopic transplantation.