Role of immune complexes in alteration of lymphocyte subpopulation numbers and functions in experimental leprosy

Swiss albino mice (normal as well as thymectomised and irradiated were inoculated into the footpads with Mycobacterium leprae and divided into two main phases of study. Phase I comprised of animals not given preformed immune complexes (IC). Uninfected controls were however included. Phase II consisted of animals given in vitro prepared IC at zero day period (OdIC), three month period (3mIC) or six month period (6mIC) to both uninfected and infected groups. Splenic lymphocytes were isolated to quantify T and B cells and their responses to M. leprae antigen and four different mitogens. Significant decrease in T cell counts and blast transformation was seen in the M. leprae infected animals which were also administered with immune complexes. Immunosuppression by IC was therefore seen to be enhanced in the presence of M. leprae infection.