Studies of Mycobacterium lepraemurium in Cell Culture

I. Continuous Multiplication in Cultures of Mouse Foot Pad CellsYoshiyasu MATSUO

Abstract

A serial increase in the number of Mycobacterium lepraemurium with successful subcultures has been obtained in the mouse foot pad (MFP) cell culture. Special attention has been given to maintaining the infected cells for longer periods; 1) the infected cells were incubated at 30 C rather than at 37 C, and 2) the concentration of serum in the culture medium was reduced from 10 to 2% as soon as a monolayer growth of the transferred cells was obtained. There have been cumulative bacterial increases of 1.47×10¹⁷ and 1.84×10¹⁵ fold for the Kurume-42 strain during a period of 1255 days, and 2.23×10⁹ and 3.89×10⁵ fold for the Hawaiian strain during periods of 831 and 572 days. The overall generation tines were estimated at 22.0, 24.8, 26.8, and 30.8 days, respectively. All attempts to grow the acid-fast bacilli obtained in cell cultures on artificial culture media have failed. The ability of the organisms to produce typical lesions in mice has been well preserved.