Immunochemical Analysis of the Specificites of IgE Antibodies Directed to Benzylpenicilloyl

The contribution that the different parts of the benzylpenicillin (BP) molecule made to the antigen-binding site was studied using human IgE sera specific to the benzylpenicilloyl (BPO) determinant. Radioallergosorbent test inhibition studies were made using in the solid phase BPO and in the fluid phase BP butylamine, 6-amino-penicillanic acid-butylamine, thiazolidine, and phenyl-acetic acid. The results indicate that the whole BPO structure was required for optimal inhibition in all sera studied and that important differences were obtained comparing these results with those obtained with the different parts of BP. These structures contributed to a different degree to the constitution of the antigenic determinant.