The effects of sera on the infection of Mycobacteria to the established cell derived from mouse were investigated in vitro. The cells used were L cell which was derived from mouse fibroblast and HeLa cell, and the strains of Mycobacteria employed were Myc. tuberculosis hominis H37Rv, H37Ra, H37Rv-INHresistant, STM-resistant, Myc. tuberculosis bovis BCG and saprophytic mycobacteria smegmatis, respectively. The following results were obtained.
1. There were some sera having different effects in the course of phagocytosis of Mycobacteria by the L cell and HeLa cell.
2. In general, it was demonstrated that the guinea pig serum promoted phagocytosis of Mycobacteria by the L cell. This promoting effect of the serum might be due to the complement-like substance because the effect was inactivated by heating at 60°C for 30 min.