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.

No abstract

Hybridomas producing monoclonal antibodies intensively reacting with group A streptococcus antigens in enzyme immunoassay were obtained as a result of immunizing mice with pepsin-treated cultures of group A streptococcus. All antibodies were referred to class M immunoglobulins. The reactions of monoclonal antibodies were completely inhibited by the pepsin-treated culture of group A streptococcus. The degree of inhibition with A-polysaccharide was lower, being 17.5 to 50.0 in different monoclonal antibodies. All the monoclonal antibodies obtained cross-reacted with antigens of murine and human epithelial tissues of the thymus and skin.

Osteoinductive activity of the transitional epithelium in the urinary bladder increased by more than 3 times in aging guinea pigs. The count of inducible osteogenic precursors and their sensitivity to urinary bladder osteoinductive factor decreased by several times with age. Our experiments show that proliferation of some stromal precursors in the spleen requires not only platelet-derived factors, but also growth factors produced by urinary bladder transitional epithelium.