Lack of Mycobacterium leprae-specific uptake in Schwann cells.

Among mycobacteria, Mycobacterium leprae have a unique property to infect peripheral nerves, which is the cause of a variety of debilities seen in leprosy. The possibility of selective uptake of M. leprae by Schwann cells was studied using a rat Schwannoma cell line 33B and rat sciatic nerve-derived Schwann cells. M. leprae were phagocytosed by 33B cells but so also were seven other mycobacteria ("Mycobacterium w," BCG, M. tuberculosis H37Rv, M. nonchromogenicum, M. vaccae, ICRC bacillus, and M. smegmatis) which do not involve peripheral nerves. All three mycobacteria tested (M. leprae, M. tuberculosis and "Mycobacterium w") were phagocytosed by sciatic nerve-derived Schwann cells. Both Schwannoma and Schwann cells phagocytosed even inert latex particles. These results fail to demonstrate any M. leprae-specific uptake system in Schwann cells.