Intranasal Immunization of Guinea Pigs with an Immunodominant Foot-and-Mouth Disease Virus Peptide Conjugate Induces Mucosal

Guinea pigs immunized intranasally with a keyhole limpet hemocyanin-linked peptide, corresponding to the prominent G-H loop of the VP1 protein of foot-and-mouth disease virus, raised substantial levels of antipeptide and virus-neutralizing antibodies in sera and of peptide-specific secretory immunoglobulin A in nasal secre-tions. In groups of animals immunized intranasally without adjuvant, 86 percent were fully protected upon challenge with homotypic virus. Surprisingly, animals given the peptide conjugates plus the mucosal adjuvant cholera toxin were afforded only partial protection in that primary lesions were observed in most animals, although spread to other feet was prevented. These results indicate that intranasal inoculation with the peptide offers a potential route of vaccination against foot-and-mouth disease and may be useful for eliciting protection in the upper respiratory tracts of susceptible animals. Vaccination against foot-and-mouth disease (FMD) is cur-rently achieved by parenteral administration of products pre-pared from tissue culture-grown virus inactivated by an aziri-dine (15). These vaccines were shown to be effective by their successful application in western Europe and some countries in South America, notably Argentina and Uruguay, followin