Experimental evidence of a decreased incidence of penicillin allergy through use of pure penicillins.

The results revealed the presence of high molecular weight impurities in commercially available penicillins, measured with a radioimmuno assay. The impurities had penicilloyl specificity and induced antibody formation in mice when the contaminated penicillin was administered in 50 mg/kg body weight daily for ten day periods with a 20 to 30 day interval. Penicillin of high purity similarly administered produced very few antibodies. Furthermore, experimentally contaminated penicillin given according to the same schedule caused IgE antibody formation against the penicilloyl moiety, while pure penicillin did not. These findings were explained by the weak immunogenicity of isologous penicilloylated serum albumin in rabbits both regarding the IgE and the IgG/IgM antibody formation compared to the immunogenicity of heterologous bovine serum albumin similarly penicilloylated.