title: In situ identification of activated Ta1+ T lymphocytes in human leprosy skin lesions.
abstract: Using a monoclonal antibody, anti-Ta1, that identifies antigen-activated T lymphocytes in vitro, we sought to identify activated T lymphocytes in leprosy skin lesions. Greater numbers of Ta1 positive T lymphocytes were observed in tuberculoid leprosy, lepromin skin tests, and reversal reactions as compared with lepromatous leprosy or erythema nodosum leprosum (ENL) (p less than 0.001). With a double-staining technique, we found that the majority of these activated T lymphocytes were of the helper/inducer phenotype. No differences of Ta1 positive lymphocytes were observed in the peripheral blood. The defective cell-mediated immune response in lepromatous and ENL patients correlates with, and may be related to the failure of T-helper/inducer activation or proliferation in the presence of Mycobacterium leprae.
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D000954:Antigens, Surface / Q000032:analysis*; D004893:Erythema Nodosum / Q000276:immunology; D006801:Humans; D007111:Immunity, Cellular; D007124:Immunoenzyme Techniques; D007918:Leprosy / Q000276:immunology*; D008213:Lymphocyte Activation; D009166:Mycobacterium leprae / Q000276:immunology*; D012867:Skin / Q000276:immunology* / Q000473:pathology; D013194:Staining and Labeling; D013601:T-Lymphocytes / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7
chemical_list: D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7