The testis in mice infected with Mycobacterium leprae

Following inoculation either locally or intravenously with Mycobact. leprae of human origin, the histopathology and bacteriology of the testis in experimental mice is described. Normal mice, and mice rendered immunologically deficient by thymectomy and whole-body irradiation, were studied. Attention is drawn to a heavy bacillation of the testis in mice from both groups. Bacilli were found in and beneath the tunica albuginea, but mainly in interstitial cells and in macrophages surrounding the tubules. The percentage of solidly staining bacilli was high, and globi were frequent. The study showed that the testis in mice is particularly favourable for the lodgement and multiplication of Mycobact. laprae following either local or intravenous inoculation. The significance of this in relation to the metabolism of the leprosy bacillus and to the frequent occurrence of testicular damage in the lepromatous male patient is discussed. This work was supported by grants to A. G. M. Weddell and A. C. McDougall from the Medical Research Council and the British Leprosy Relief Association (LEPRA).