Immunologic Cross-reactivities of Three Diverse Penicillins.

RECENT investigations have demonstrated the importance of the benzylpenicilloyl group as an antigenic determinant in benzylpenicillin (PG) hypersensitivity (Levine and Ovary, 1961) (Fig. 1). It has been suggested that this antigen is formed by the conjugation to protein of the highly reactive intermediate, benzylpenicillenic acid (Fig. 1, B). A number of conventional penicillins derived from 6-aminopenicillanic acid (6-APA) form penicillenic acid at varying rates and all those that have been tested crossreact immunologically with PG.