Lymphocyte subpopulations in mice infected with Mycobacterium leprae.

T and B cells were quantitated from the spleen of M. leprae infected mice and correlated with bacillary count in the foot pad. Lymphocyte transformation with PHA and M. leprae (armadillo) antigens was also studied during different months of infection. T cell counts dropped gradually but significantly throughout the course of infection. B cells had a concomitant rise up to 6 months and then registered a fall as compared to the initial control figures. Transformation of lymphocytes with PHA fell significantly after 4th month til the end of the experiment, whereas stimulation index for armadillo antigen rose gradually from 3rd month onwards to reach a peak at 6th month and then fell till the end of the experiment with increasing bacterial population whereas B-cell counts showed little change.