Antigenic and allergenic determinants of ovalbumin—III. MHC Ia-binding peptide (OA 323–339) interacts with human and rabbit specific antibodies

Abstract

Three analogous peptides mimicking the known primary structure of ovalbumin (OA) in the region 323–339 (namely, OA 323–339, OA 323–338 and OA 324–336) were manually synthesized by the Merrifield solid phase technique. The synthetic preparations were purified by gel filtration and ion exchange high performance liquid chromatographies. The sequence linearities were deduced from the amino acid composition prior to each stage of coupling and the amino acid sequence determination on the ultimate chain. OA 323–339 was conjugated to BSA, using carbodiimide activation of the carrier protein and the conjugated compound was further used for production of antibodies in rabbit. The results showed that the region OA 323–339 was immunogenic; it could give immunoprecipitates with rabbit anti-OA 323–339-BSA in crossed immunoelectrophoresis (CIE). It similarly could bind human specific IgE from serum pools from patients allergic to egg in crossed radio immunoelectrophoresis (CRIE). Quantitative precipitation inhibition and specific IgE inhibition were used for confirming the antigenic and allergenic activities of this region. The results led us to conclude that the region 323–339 of the OA molecule encompassed an allergenic and antigenic epitope which were recognized by human and rabbit B-cells.