Eliciting IgE-mediated passive cutaneous anaphylactic reaction by synthetic D-benzylpenilloic acid analogs

The ability of various D-benzylpenilloic acid analogs to evoke the passive cutaneous anaphylactic (PCA) reaction was tested in rats sensitized with mouse IgE antibodies to a benzylpenicillin preparation. D-benzylpenilloic acid synthesized chemically from materials that had no potency to evoke the PCA reaction showed almost the same antigenicity in eliciting the reaction as that prepared from benzylpenicillin. Changes in the chemical structures of the side-chain and thiazolidine ring of D-benzylpenilloic acid resulted in a reduction in the activity, but the removal of either alpha- or beta-methyl did not greatly affect it. From these results, it was concluded that benzyl and amidomethyl at C-2, the D-configuration at C-4, and dimethyl at C-5 on the thiazolidine ring have a significant effect on the PCA reaction.