title: Epithelioid cell granuloma induction in the guinea pig by haptenated Mycobacterium leprae.
abstract: Fluorescein isothiocyanate (FITC)-conjugated Mycobacterium leprae (FITC-M. leprae) was injected intradermally into the ears of guinea pigs and granuloma formation in the draining postauricular lymph nodes was studied. At 2 weeks, there was an increase in weights and infiltration of the draining lymph nodes in half of the animals injected with FITC-M. leprae. At 5 weeks, there was a significant increase in the weights and infiltration of these draining lymph nodes in the guinea pigs injected with haptenated M. leprae compared with those injected with unconjugated M. leprae. At 5 weeks, there was also a significant increase in delayed type hypersensitivity responses to 25 micrograms purified protein derivative. Histologically, epithelioid cell granulomas were seen in these lymph nodes as early as 2 weeks when FITC-M. leprae was used as the source of antigen. Enhancement in the immunogenicity of M. leprae by conjugation with FITC has been postulated.
mesh_terms: D000818:Animals; D004848:Epithelium / Q000473:pathology; D016650:Fluorescein-5-isothiocyanate; D005452:Fluoresceins; D006099:Granuloma / Q000276:immunology* / Q000473:pathology; D006168:Guinea Pigs; D006241:Haptens; D006968:Hypersensitivity, Delayed / Q000276:immunology; D007111:Immunity, Cellular; D007918:Leprosy / Q000276:immunology* / Q000473:pathology; D008198:Lymph Nodes / Q000473:pathology; D009166:Mycobacterium leprae; D010586:Phagocytes / Q000473:pathology; D013861:Thiocyanates; D014373:Tuberculin / Q000276:immunology
chemical_list: D005452:Fluoresceins; D006241:Haptens; D013861:Thiocyanates; D014373:Tuberculin; D016650:Fluorescein-5-isothiocyanate