Association of macrophage lipids with Mycobacterium lepraemurium in the mouse thymus and lymph node.

Mice infected systemically with (“rat leprosy bacillus”), an obligate intracellular parasite, showed uneven spread of triglyceride, phospholipids, and certain unsaturated fatty-acids in infected macrophages throughout the lymphoid system (determined histochemically and by chromatographic analysis). Such materials were abundant in parasitised macrophages in the thymus, but little or none were demonstrable in parasitised macrophages in the lymph node medulla; only relatively small amounts were present in the few affected cells in the lymph node cortex. Lipids apparently influenced bacillary multiplication, for multiplication was greater in macrophages in the thymus than in the lymph node, despite much lysosomal activity.