Growth of Mycobacterium lepraemurium in cultures of macrophages obtained from various sources

Studies were made on the growth of Mycobacterium lepraemurium in cultures of macrophages obtained from various sources, such as bone marrow, spleen, and blood of mice. Macrophages were maintained in good condition for more than 12 weeks. Marked intracellular multiplication of M. lepraemurium was observed in cultures from all three sources. Whereas M. lepraemurium freshly prepared from the animals showed good growth in the cultures, those that were kept at 4 degrees C for 10 or 14 days showed no growth.