Antigenic analysis (IgE and monoclonal antibodies) of the major shrimp allergen Pen a 1 (Tropomyosin) from Penaeus aztecus
International Archives of Allergy and Immunology
G ReeseS B Lehrer
Abstract
Pen a 1, the major shrimp allergen from the brown shrimp Penaeus aztecus was purified by preparative SDS-PAGE. Peptides were generated from Pen a 1 by CNBr cleavage and endoproteinase (Lys-C, Glu-C, trypsin, alkaline protease, Arg-C, chymotrypsin) digestion. The molecular weights of the resulting CNBr cleavage and enzymatic digestion products, separated by peptide SDS-PAGE, ranged from 1.5 to 20 kD. Following SDS-PAGE and semidry blotting, the analysis of monoclonal antibody (mAb) and subjects' IgE reactivities demonstrated that with the exception of alkaline protease, all cleavage procedures yielded IgE-binding peptides. However, since not all peptides of every digest bind IgE, it appears that IgE-binding epitopes are restricted to certain parts of the Pen a 1 molecule. mAbs bound to CNBr, Lys-C, trypsin, Glu-C and Arg-C peptides. Since mAbs reacted to several peptides from the same digest, Pen a 1 may have several similar epitopes. The comparison of IgE and mAb reactivities demonstrated similar but not identical binding patterns.