Immediate hypersensitivity in the guinea pig conjunctiva intravitreal and topical sensitization

The right eyes of guinea pigs were injected with 1.5 mg sterile ovalbumin. Two months later, one drop of ovalbumin (approximately 0.6 mg) was applied to the conjunctiva of both eyes. All challenged eyes developed an immediate hypersensitivity reaction within 5 min. The reaction subsided within 2 hrs. Prechallenge antibody titers, as determined by passive hemagglutination, passive cutaneous anaphylaxis, and by an ELISA test were low. Titers rose rapidly after two conjunctival applications at weekly intervals. The hypersensitivity reaction was elicited each time antigen was applied to the conjunctiva of the intravitreally sensitized guinea pigs. Control guinea pigs received weekly conjunctival application of ovalbumin, without prior intravitreal sensitization. Most animals developed an immediate hypersensitivity reaction following the fourth application of the antigen. There was no detectable hemagglutinating or ELISA (IgG1, IgG2) antibody at the time the conjunctival reaction was first elicited. These experiments demonstrated that high circulating IgG1 or IgG2 antibody is apparently not necessary to initiate an immediate hypersensitivity reaction in the guinea pig conjunctiva. The authors also demonstrated that weekly topical application of ovalbumin sensitized guinea pigs for immediate hypersensitivity.