Myco. leprae infection in normal, thymectomised irradiated and thymus transplanted mice

Normal mice and thymectomised, X-irradiated and thymic transplanted groups of mice were challenged with 10(3) Myco. leprae in the foot pad. Course of infection was studied for a period of seven months by sacrificing animals every month and counting the bacilli from the pooled tissues. In the thymectomised irradiated group the counts showed a plateau from 5th month onwards, whereas in control and thymus implant group the counts rose in 6th and 7th months.