title: Antibody responses to the 18-kDa protein of Mycobacterium leprae in leprosy and tuberculosis patients.
abstract: The 18-kDa protein of Mycobacterium leprae, as recognized by the monoclonal antibody L5, has a restricted species distribution, being confined to M. leprae and M. habana. We have developed a solid-phase ELISA using purified, recombinant M. leprae 18-kDa protein and compared the serological responses of Nepali leprosy and tuberculosis patients and endemic control subjects to the protein and the M. leprae phenolic glycolipid-I (PGL-I). Few control subjects had anti-18-kDa antibodies. A small proportion of paucibacillary (PB) leprosy and 42% of multibacillary (MB) leprosy patients had IgG anti-M. leprae antibodies. A similar proportion (47%) of Nepali tuberculosis (TB) patients were seropositive, and IgG anti-18-kDa antibody levels were significantly higher in MB and TB patients than in control subjects. By comparison, IgM anti-PGL-I antibodies were detected in 88% of MB leprosy patients and only 7% of TB patients. The possible reasons for the 18-kDa protein seroreactivity in TB patients are discussed, and the anti-18-kDa assay is compared with other antibody assays for protein and nonprotein antigens of M. leprae. It is concluded that the sensitivity and specificity of the anti-M. leprae 18-kDa ELISA are insufficient for the assay to be of clinical utility in leprosy patients.
authors.affiliation: Mycobacterial Research Laboratory, Anandaban Leprosy Hospital, Kathmandu, Nepal.
authors.forename: P W
authors.initials: PW
authors.lastname: Roche
authors.forename: R L
authors.initials: RL
authors.lastname: Prestidge
authors.forename: J D
authors.initials: JD
authors.lastname: Watson
authors.forename: W J
authors.initials: WJ
authors.lastname: Britton
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000096:biosynthesis* / Q000097:blood; D000911:Antibodies, Monoclonal / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology; D001426:Bacterial Proteins / Q000276:immunology*; D002648:Child; D000939:Epitopes / Q000276:immunology; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000097:blood; D007075:Immunoglobulin M / Q000096:biosynthesis / Q000097:blood; D007918:Leprosy / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009166:Mycobacterium leprae / Q000276:immunology*; D011994:Recombinant Proteins / Q000276:immunology; D014397:Tuberculosis, Pulmonary / Q000276:immunology*
chemical_list: C067864:18 kDa protein, Mycobacterium leprae; D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D000939:Epitopes; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011994:Recombinant Proteins