[Proliferation and splenic migration of mouse hematopoietic stem cells following a single injection of Mycoplasma arthritidis].

The effect of a single injection of live M. arthritidis microorganisms on the bone marrow and spleen CFU-S populations was assessed. One of the principal findings is that marrow CFU-S are recruited into cell cycle (as determined by hydroxyurea kill) early after M. arthritidis administration and stay in the cycle for at least 2 weeks thereafter. The peak level of cycling value (47%) was observed on day 4. The duration of increased CFU-S cycling activity was shown to coincide with a time period during which a significant rise in the number of endogenous CFU-S was maintained. The other important finding is that splenic seeding efficiency ("f-factor") declines by 56% one day following M. arthritidis administration. The latter effect could be attributed to the binding of mycoplasmas to the surface of CFU-S as specific rabbit antiserum against M. arthritidis incubated in vitro with the bone marrow cells of infected donor mice caused an up to 48% reduction in the in vivo colony-forming ability of CFU-S.