Pathology Research Department, Pharmacology Research Department, and Laboratory Research Branch, National Hansen's Disease Center, Department of Anatomy, Louisiana State University Medical Center, Carville, Louisiana 70721
Liver tissue from a nude mouse infected with Mycobacterium leprae for 18 months was examined using light and electron microscopes. Numerous microgranulomas composed of macrophages were present throughout the liver. M. leprae in large numbers were present in Kupffer cells, macrophages, endothelial cells, and liver parenchymal cells. The study shows that the lower temperature of about 31°C optimal for the growth of M. leprae is relative rather than absolute, and that M. leprae can invade even liver cells.