title: Development of a mucosal challenge test for leprosy using leprosin A.
abstract: There is little information about the mucosal immune response in leprosy. We have developed a nasal provocation test with leprosin A which will be used to investigate mucosal immunity to Mycobacterium leprae. Initial studies were performed with increasing doses of leprosin A (1.0 pg/ml-10 micrograms/ml) to determine the optimal safe dose of leprosin A. Anti-M. leprae IgA antibody and normal IgA concentrations were measured in the saliva of leprosy contacts and controls before and after instillation of leprosin A. Nasal leprosin A was well tolerated up to a concentration of 10 micrograms/ml without side effects. None of the six subjects who had not been exposed to leprosy had salivary IgA against whole M. leprae, whereas IgA was detected from 64 h to 140 h following instillation of leprosin A in all of the leprosy hospital workers and in 15 out of 18 healthy household contacts tested. There was no correlation between serum and salivary anti-M. leprae IgA levels before and after testing. Salivary IgA anti-lipoarabinomannan responses were seen in 12 out of 20 household contacts. Normal salivary IgA concentrations varied from 8 to 240 mg/l. The leprosin A nasal provocation test appears to be a safe method for the investigation of the role of mucosal immunity in the pathogenesis of leprosy.
authors.affiliation: Stanley Browne Laboratories, Richardson Leprosy Hospital, Leprosy Mission, Miraj, India.
authors.forename: P
authors.initials: P
authors.lastname: Ramaprasad
authors.forename: I A
authors.initials: IA
authors.lastname: Cree
authors.forename: M
authors.initials: M
authors.lastname: Oluwole
authors.forename: P D
authors.initials: PD
authors.lastname: Samson
mesh_terms: D000293:Adolescent; D000328:Adult; D000942:Antigens, Bacterial / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis; D007071:Immunoglobulin A, Secretory / Q000032:analysis; D007918:Leprosy / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009166:Mycobacterium leprae / Q000276:immunology*; D009297:Nasal Mucosa / Q000276:immunology* / Q000378:metabolism; D009299:Nasal Provocation Tests / Q000379:methods*; D012463:Saliva / Q000276:immunology; D014373:Tuberculin
chemical_list: D000942:Antigens, Bacterial; D007070:Immunoglobulin A; D007071:Immunoglobulin A, Secretory; D014373:Tuberculin; C041383:leprosin A