Pathogenicity of cultivated murine leprosy bacilli Hawaiian-Ogawa strain in mice. 1. The pathogenicity of bacilli from rough colonies.

This paper deals with the pathogenicity of cultivated murine leprosy bacilli from rough colonies of Hawaiian-Ogawa strain in mice. This strain was isolated by Ogawa, in 1970, on Ogawa's 1% egg yolk medium [1], from mice previously inoculated with Hawaiian strain of murine leprosy bacilli which has been maintained by passages from mice to mice. The pathogenicity of Hawaiian-Ogawa strain was found to belong to the same pattern as Hawaiian strain when the subcutaneous inoculation test was carried out in C57BL/6 and C3H mice, the former being representative of the benign type and the latter being representative of the malignant type. In KK mice of the intermediate type with Hawaiian bacilli, however, Hawaiian-Ogawa bacilli produced the lesions with malignant features in almost all the male mice, while the female mice were divided into two groups roughly half showing the intermediate or malignant type. In DDD mice of the benign type with Hawaiian bacilli, some cases of the male mice showed the malignant features, whereas almost all the female mice were of the benign type in the same experimental conditions. The pathogenicity of Hawaiian-Ogawa bacilli in mice did not revert into that of Hawaiian bacilli even after serial mouse passage. There are slight but definite differences in the mouse pathogenicity between Hawaiian-Ogawa and Hawaiian strains.