Abilities of human oligodendroglial cells and mouse Schwann cells to phagocytose Mycobacterium leprae and other mycobacteria.

Human oligodendroglial KG-1-C cells derived from human cerebral mixed glioma and mouse Schwann cells derived from dorsal root ganglion were studied with respect to their abilities to phagocytose various mycobacteria, especially Mycobacterium leprae, and other microorganisms. KG-1-C cells phagocytosed M. leprae at a markedly higher rate than BALB/3T3, BHK 21, HeLa S3, mKS-A TU-7, XC, TSV-5, N-18, and Schwann cells but at a lower rate than peritoneal macrophages. Schwann cells also exhibited substantial phagocytic ability against M. leprae, and their phagocytic rate against M. leprae was much higher than that of N-18 cells, derived from neurons. KG-1-C and Schwann cells phagocytosed mycobacteria other than M. leprae, and their phagocytic patterns with various mycobacteria were similar, thereby suggesting that their abilities to phagocytose mycobacteria were based on the same cellular mechanism. The time course of phagocytosis of M. leprae by KG-1-C cells markedly differed from that by macrophages, indicating differences in the cellular mechanisms of M. leprae phagocytosis. KG-1-C cells also ingested microorganisms other than acid-fast bacilli, such as Staphylococcus aureus, Listeria monocytogenes, Bacillus subtilis, and Escherichia coli but not Candida albicans. They also phagocytosed latex beads (0.8-micron diameter) but not sheep erythrocytes. Microscopically, most mycobacterial cells were ingested in the perikaryon of KG-1-C cells and Schwann cells.