Effect of Serum from Mice Immunized with Group A Streptococcus Antigens on the Efficiency of In Vitro Cloning of Stromal Precursor Cells

The efficiency of cloning of stromal precursor cell in mouse bone marrow culture increases significantly (2–3-fold) in the presence of serum from mice immunized with type 5 group A streptococcus antigens (5-20 μl serum/ml culture medium) in comparison with intact animal serum. The levels of TNF-α and IFN-γ are significantly reduced (2.7 times and more than 6-fold, respectively) in the sera of immunized mice in comparison with normal serum. Serum levels of IL-2, -4, -5, -10, and -12 were about the same in both groups; no granulocyte-macrophage CSF was detected. These data attest to appreciable effect of immunization with streptococcal antigens on the bone marrow stromal tissue; this effect is presumably mediated through serum cytokines.