BCG induced immunity to Mycobacterium leprae in mice

One to three BCG vaccinations were given to various groups of mice--25 to 2 days preceding challenge with Myco. leprae. Harvesting of Myco. leprae was done every month upto a period of 7 months. Lymph node enlargement was taken as an indicator of successful vaccination. An increasing degree of protection was noted in BCG immunised mice as observed by a reduced number of bacilli harvested. Protection afforded was proportional to the number of doses of BCG given.