title: Lymphocyte suppression in leprosy induced by unique M. leprae glycolipid.
abstract: Leprosy remains a significant medical and social problem in many developing countries. The varied forms of the disease form a spectrum. At one pole, tuberculoid leprosy, patients develop high levels of cell-mediated immunity which results in the killing and clearing of bacilli in the tissues. At the lepromatous pole, patients exhibit a selective immunological unresponsiveness to antigens of Mycobacterium leprae so that the organisms inexorably multiply in the skin. We have suggested that in lepromatous leprosy one or a small number of unique antigenic determinants present on M. leprae might induce specific suppressor cells that inhibit the reactivity of helper T-cell clones capable of recognizing other specific or cross reactive determinants. Although unique epitopes have been identified by monoclonal antibodies on a small number of M. leprae proteins, the only unique species of antigen present in M. leprae, and not on any other species of mycobacteria so far examined, is a phenolic glycolipid (gly-I). We show here that this unique antigen of M. leprae is capable of inducing suppression of mitogenic responses of lepromatous patients' lymphocytes in vitro and provide evidence that the suppressor T cells recognize the specific terminal trisaccharide moiety.
mesh_terms: D000942:Antigens, Bacterial / Q000276:immunology*; D006017:Glycolipids / Q000276:immunology*; D006801:Humans; D007165:Immunosuppression Therapy; D007918:Leprosy / Q000276:immunology*; D008081:Liposomes; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology*; D009161:Mycobacterium / Q000276:immunology; D009166:Mycobacterium leprae / Q000276:immunology*; D013045:Species Specificity
chemical_list: D000942:Antigens, Bacterial; D006017:Glycolipids; D008081:Liposomes