title: Cellular and humoral immune response to a phenolic glycolipid antigen (PhenGL-I) in patients with leprosy.
abstract: The ability of phenolic glycolipid I (PhenGL-I) of Mycobacterium leprae to stimulate in vitro lymphocyte proliferation (LP) was tested in cultures of peripheral blood cells from 42 patients with leprosy in Chicago and Thailand, 9 individuals with household contact in Thailand, and 10 unexposed North American controls. Only 10 responders (24%) were found among the patients, and the degree of LP was small. Responders were found among patients with lepromatous (18%) or tuberculoid (30%) leprosy without relation to age, complications, duration of treatment, or lepromin responsiveness. The specificity of the response was supported by a lack of response to two other glycolipids, by responses by T cells but not B cells, and by the observation that three of four responders tested maintained their responses to PhenGL-I for at least 1 year. Serum immunoglobulin M (IgM) and IgG antibodies were measured in the same patients by using PhenGL-I or its terminal monosaccharide conjugated to a bovine serum albumin carrier in an enzyme-linked immunosorbent assay. The presence of IgM antibody correlated negatively with LP to lepromin and to PhenGL-I in patients with tuberculoid leprosy. We conclude that circulating T cells from some leprosy patients proliferate in the presence of PhenGL-I in vitro, but the response is weak, possibly due to concomitant suppression or inhibition. The predominance of IgM antibody to PhenGL-I may be related to a lack of a T-helper-cell-mediated switch to IgG antibody response.
mesh_terms: D000907:Antibodies, Bacterial / Q000032:analysis; D000942:Antigens, Bacterial / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D005260:Female; D006017:Glycolipids / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D007916:Lepromin / Q000276:immunology; D007918:Leprosy / Q000276:immunology*; D008137:Longitudinal Studies; D008213:Lymphocyte Activation; D008297:Male; D009166:Mycobacterium leprae / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D006017:Glycolipids; D007074:Immunoglobulin G; D007075:Immunoglobulin M; C045169:phenolic glycolipid I, Mycobacterium leprae; D007916:Lepromin