Lymphoproliferative responses of leprosy patients and healthy controls to nitrocellulose-bound M-leprae antigens

The lymphoproliferative responses of 51 leprosy patients and 11 healthy con tacts were analyzed using the nitrocellulose-bound specific antigen fractio ns from the cell-free extract of Mycobacterium leprae. The main proliferati on-inducing fraction for peripheral blood mononuclear cells of the healthy contacts was found to be the Fraction II, bearing antigens in the range of 66-45 kDa. However, this fraction failed to induce lymphoproliferation in t he leprosy patients, unlike healthy contacts (p <0.032). The number of resp onders as well as the strength of the responses to 66-45 kDa proteins were found to be low in the leprosy patients compared to the healthy contacts. F urther, preliminary analysis with the subfractions of Fraction Pi produced a similar pattern, suggesting that the immune response to the antigens in t he range of 66-45 kDa M. leprae proteins remains suppressed in subjects wit h clinical signs and symptoms of the disease.