The problem of cultivation of Mycobacterium leprae. A review with criteria for evaluating recent experimental work.

Some criteria are presented to help evaluate papers appearing in the literature claiming successful cultivation of M. leprae either in the absence or in the presence of tissue-cultured cells. Recently, electron microscopic studies have definitely shown M. leprae to belong to the genus Mycobacterium and its division to occur through transverse section. A survey is given of the mycobacterial strains isolated in the last 10 years from leprosy lesions. These strains belong to taxonomically different species and cannot be considered to be M. leprae. No substantiated claim was made concerning the in vitro growth of M. leprae and the application of the tissue culture technique has been equally disappointing. The view is expressed that progress towards the in vitro cultivation of M. leprae can be made only as a result of increased knowledge about the intracellular environment and the metabolic activities of this organism, to be obtained by the application of modern biochemical and histochemical techniques.