Studies on the generation of biologically active substances by Trypanosoma theileri in vitro.

Trypanosoma theileri was grown in bovine primary spleen cell cultures. These organisms were tested for phospholipase activity which was found to be very low, for haemolytic activity which was very weak and for lymphocyte mitogenicity which was found to be absent. High concentrations of T theileri were found to activate bovine complement probably by both the alternate and classical pathways. There was no evidence that these organisms exerted any significant toxic effect in vitro or in vivo. This is compatible with the known low pathogenicity of this species.