Effects on in vitro growth of Babesia microti by cells and serum from B. microti and Schistosoma mansoni infected mice.

The effect of peritoneal macrophages and serum from mice infected with and plus on the growth of was assessed in short term in vitro cultures using the criterium of rate of incorporation of (H)Hypoxan-thine. In the absence of serum, macrophages and supernatants from macrophage cultures failed to affect the in vitro growth of In contrast, in the absen-de of macrophages, serum from mice infected with and with plus induced a marked inhibition of the in vitro growth of The level of inhibition induced by serum from mice infected with both and exceeded consistently that induced by serum from mice infected with only. Serum from mice only infected with induced a marked increase in the in vitro growth of These findings suggest a suppression of in concurrently mice induced by an immunological specific anti-2?. factor potentiated by the concurrent infection. The results do not indicate that activation of the mononuclear phagocytic system is of primary importance in suppression of in-concurrently infected mice.