Induction and down-regulation of conjunctival type-I hypersensitivity reactions in guinea pigs sensitized topically with fluoresceinyl ovalbumin.
Type-I hypersensitivity reactions were induced in guinea pigs by repeated topical/conjunctival application of fluoresceinyl ovalbumin (FL-OA). The ocular reactivity in early responding animals was maximal between 16 and 25 days and decreased exponentially thereafter. Desensitized eyes responded minimally to compound 48/80 but maximally to histamine. Unilateral sensitization and challenge with FL-OA produced desensitization of the immunized eye, but the reactivity of the contralateral eye persisted. A significant reduction in conjunctival stained mast cells was found in repeatedly challenged eyes. The desensitization therefore was due to a loss of reactive mast cells. Systemic infection with Ascaris suum, after repeated topical challenge with FL-OA had led to desensitization, produced a reappearance of type-I hypersensitivity reactions toward both FL-OA and ascarid antigens.
D000287:Administration, Topical; D000818:Animals; D001196:Ascariasis / Q000276:immunology; D003229:Conjunctival Diseases / Q000276:immunology* / Q000473:pathology; D003888:Desensitization, Immunologic; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006168:Guinea Pigs; D006632:Histamine; D006967:Hypersensitivity / Q000276:immunology* / Q000473:pathology; D007114:Immunization; D008407:Mast Cells / Q000473:pathology; D010047:Ovalbumin / Q000031:analogs & derivatives* / Q000276:immunology; D003189:p-Methoxy-N-methylphenethylamine
C042851:fluorescein-ovalbumin; D003189:p-Methoxy-N-methylphenethylamine; D006632:Histamine; D010047:Ovalbumin