ABSTRACT
Delipidified cell components (DCC) of Mycobacterium leprae obtained as an insoluble material consist of several proteins. This preparation, DCC, has ability to differentially bind to sera from lepromatous leprosy patients and antibodies to this complex get reduced as patients improve under chemotherapy. The antigenic complex has no ability to bind to proteins of sera from normal healthy individuals or tuberculoid leprosy patients. The DCC is antigenic and is recognised by immune deficient cells of lepromatous leprosy patients, leading to lymphocyte proliferation, production of Interleukin II and interferon gamma, and resulting in activation of the phagocytes to initiate killing of endocytosed M.leprae through reactive oxygen intermediates, primarily superoxide. The DCC has also immunomodulatory properties to protect mice against M.leprae infection. Experiments with mice and isolated peripheral blood cells from patients have indicated the probable molecular mechanism of immunomodulation by DCC.