Penicillin allergy and the heterogenous immune responses of man to benzylpenicillin.

The administration of benzylpenicillin (penicil- lin) to man has been shown to induce the synthesis of antibodies of several distinct haptenic speci- ficities and of several molecular classes (1-13). Specifically, skin-sensitizing antibodies of benzyl- penicilloyl (BPO) haptenic specificity (1-7, 11) and of the minor determinant specificities (6, 7, 11) have been demonstrated. Also, BPO-specific antibodies of IgM and IgG classes have been iden- tified in serum by passive hemagglutination (3-5, 8-10, 12, 13). We now report the results of as- says for BPO-specific IgM, IgG, and skin-sensitizing antibodies, and minor determinant specific skin-sensitizing antibodies in various groups of pa- tients with and without recent allergic reactions to penicillin. The data obtained describe the hetero- geneous immune responses to penicillin made by human beings and permit initial inferences as to the nature of the immunological mechanisms that mediate allergic reactions to penicillin.'