Analysis ofimmuneresponsesinthesheep tosynthetic peptides offoot-and-mouth disease virus using ovinepolyclonal and monoclonal antibodies

SUMMARY A 40-residue peptide incorporating residues 200-213 and141-158 offoot-and-mouth disease virus VP1capsid protein strain 01 Kaufbeuren was injected uncoupled intosheep, andtheimmune responsesanalysed. Direct-binding andinhibition experiments showedthatthepolyclonal antibody responsewasdirected mainly against epitopes unique tothe40-residue peptide butabsent fromthe constituent peptides containing residues 200-213 or141-158, respectively. Further confirmation of thepresenceofunique epitopes on the40-residue peptide was obtained fromsimilar experiments performed withsheep monoclonal antibodies generated through theuseofanaminopterin-sensitive sheep/mouse heterohybridoma cell line asafusion partner. Thesheep polyclonal antisera tothe40residue peptide hadhighneutralization titres andwere fully active ina mouse protection assay, whereas noneofthesheep monoclonal antibodies conferred protection. Theresults suggest thatthe conformation ofthe40-residue peptide isimportant foritsability toinduce neutralizing antibodies.