Growth of the ICRC bacilli in the foot-pad of mice.

The ICRC bacilli are acid-fast bacilli cultivated from M. leprae isolates of lepromatous tissue. The ICRC bacilli from C-44 in the conditioned medium were subjected to foot-pad test, in both normal and T/900r mice. The bacilli exhibits a limited multiplication in normal mice while a continuous growth in T/900r mice. The maximum yield for normal and T/900r mice was 10(7) and 10(9)/foot-pad, respectively. The infiltration of voluntary muscle tissue as the main localization site was common for both normal and T/900r mice with evidence of dissemination in the latter. The spread of AFB to sciatic nerve, induction of liver granuloma and the foot-drop was observed only in T/900r mice. These experiments show that the growth of ICRC bacilli in mouse foot-pad is very similar to that of M. leprae confirming a test for identification.