[Difference in infectivity of Mycobacterium leprae from patients in immunosuppressed mice (author's transl)].

Leprosy bacilli obtained from twenty lepromatous leprosy patients were inoculated in the testis of different immunosuppressed mice. These detailed results were reported before (4, 5, 6, 7, 8, 9, 10). The various immunosuppressed mice were: Na131I 100μci injected mice (I-P) (4), and their offsprings (I-F) (5); 60Co 300R irradiated mice (R-P) (6), and their offsprings (R-F) (7); Na131I 100μci injected and also 60Co 300R irradiatiated mice during their fetus term (IR-F) (6); anti-lymphocytic serum injected mice (ALS) (8); and nude mice (BALB/c-nu/nu) (9). Acid-fast bacilli (globi, +G) were observed in the stamp-smear samples of the in oculated site about ten months after injection. Two of the 20 strains of leprosy bacilli from the patients showed infective activity in both the immunosuppressed and non-immunosuppressed mice. These two strains (LL28 & LL44) were put together in a group designated "A". But the percentage of infectivity in the immunosuppressed mice was greater than that in the non-immunosuppressed mice.Ten strains (eight in Table 3 and two in Table 6) showing multiplication of M. leprae in the immunosuppressed mice alone were put together in a group designated "B". The remaining eight strains (Table 3) which were negative in both the immuno suppressed and non-immunosuppressed mice were put together in a group designated "C". There was no relationship between the above mentioned immunosuppressed mice and the bacilli of Group A, B and C.One strain, LL44 of Group A; two strains, LL49 and LL51 of Group B; and one strain, LL45 of Group C were pathogenic for the nude mice, but the virulence of Group C leprosy bacilli was less than that of Group A and B.