Antigenicity of semisynthetic penicillin preparations to evoke systemic anaphylactic reactions in animal models

Four commercially available penicillin preparations (benzylpenicillin, aminobenzylpenicillin, carbenicillin and sulbenicillin) and two kinds of the new semisynthetic penicillin preparations (mezlocillin and piperacillin) evoked systemic anaphylactic reactions in guinea pigs immunized with one of the following penicillin-Ascaris extract (As) conjugates in aluminum hydroxide gel (alum), i.e., benzylpenicilloyl (BPO)-As, aminobenzylpenicilloyl (ABPO)-As, carbenicilloyl (CBPO)-As, sulbenicilloyl (SBPO)-As, mezlocillin-As conjugate (MEZ-As) and piperacillin-As conjugate (PIP-As). The tracheal chains prepared from the tracheas of the guinea pigs immunized with BPO-As, MEZ-As, or PIP-As revealed anaphylactic contractions in vitro on addition of benzylpenicillin, mezlocillin, or piperacillin preparations. These results indicated that the semisynthetic penicillin preparations as well as benzylpenicillin preparation have enough antigenicity to evoke systemic anaphylactic reactions in guinea pigs immunized with penicillin-As conjugate. Such guinea pigs seem to be suitable animals for investigations of penicillin allergy.