抄録
As stated in the preceding report, mice of CF#1 strain were of the intermediate characteristics in their response to subcutaneous inoculation with murine leprosy bacilli, their subcutaneous leproma being benign but the visceral lesions developing severe as observed in the malignant cases. Taking these characteristics into our consideration, effects of BCG were investigated on the development of murine leprosy in CF#1 mice.
Thirty mice of CF#1 strain were divided into 3 groups (A, B and C) . The animals of Group A were inoculated intraperitoneally with 1.0 mg of living BCG, while those of Group B were inoculated subcutaneously with 5.0 mg of killed murine leprosy bacilli suspended in incomplete adjuvant (Freund). The Remainder, mice of Group C, were used as controls. Challenge infection with 0.25 cc of a 1:1000 suspension prepared from leproma was made 4 weeks after vaccination. As shown in Tables 1, 2 and 3, the effects of vaccination were followed not only by the develop-ment of subcutaneous leproma, but also by the severity of visceral lesions.
In Group A, 3 of experimental animals died within 32 weeks after challenge infection. But it is obvious that their death was not caused by murine leprosy, because of small benign leproma at the inoculation site and slightness of the visceral lesions. Therefore, these 3 mice were eliminated from discussion of the present study. Five of the remaining mice died in 60 to 64 weeks and the other 2 were sacrificed at the end of experiment. The visceral lesions of 2 dead mice were severe, whereas those of the other 5 mice, 3 died and 2 sacrificed, were very slight. All the challenged mice showed benign, or near benign type leproma at the inoculation site in the course of this infection.
In Group B, effects of vaccination were investigated in eliminating 2 mice, died at the early stage, as discussed in Group A. Half of the remaining 8 mice, died in 48 to 60 weeks, showed much more severe visceral lesions than the others. And the lungs of 3 sacrificed mice showed severe involvement whereas the other organs thereof showed very slight. All experimental animals but one showed the benign type leproma at the inoculation site, but in one exception a conversion of the benign type to the malignant one was observed at the late stage of infection.
In the mice of Group C challenge infection resulted in death within 44 to 56 weeks, with extensive involvement of the visceral organs. A conversion similar to that observed in Group B occured in several cases of challenged mice, in which subcu-taneous leproma was found to be benign.
It is evident from these results that the development of visceral lesions progressed more slowly in CF#1 mice vaccinated with BCG or killed murine leprosy bacilli than in the controls, and survival time of the challenged mice could be prolonged by the vaccinations. Moreover it is interesting to note that BCG is superior to the killed bacillus vaccine in many aspects, especially in suppression of the development of murine leprosy in lungs.
