Electron microscopic findings of transverse fission of M. leprae by freeze-etching methods.

The structures of multiplication by transverse fission found in the lepromas and livers of nude mice and nine-banded armadillos inoculated with Mycobacterium leprae isolated from human lepromas, a nine-banded armadillo with naturally acquired leprosy-like disease, and a nine-banded armadillo inoculated with M. leprae isolated from the mangabey monkey with naturally acquired leprosy infection are described. The images of multiplication by transverse fission of M. leprae were almost always found inside the phagolysosomes of lepra cells. At the time of multiplication by transverse fission, band structures were observed generally at both sides of the fission line. According to these results, multiplication of M. leprae by transverse fission is done inside the phagolysosomes of lepra cells of nude mice and nine-banded armadillos.