Limited Multiplication of Mycobacterium lepraemurium in Cell Cultures

Abstract

Following in vitro incubation of spleen cells from M. lepraemurium infected mice, quantitative determinations revealed that the bacillary content increased 2-3 fold. Earle''s L strain of mouse fibrocytes, maintained in defined medium containing 2% horse serum and 0.5% Bacto-peptone, were infected in vitro with suspensions of M. lepraemurium. The L cell also supported a 2-3 fold increase in bacillary numbers provided 0.2 mg/ml of hydrocortisone was incor-porated in the culture medium. Rates of multiplication during the first two weeks of incubation approximated the maximum rates observed in vivo. However, the in vitro system described did not allow significant increases after this period.