Benzylpenicilloyl-Specific Serum Antibodies to Penicillin in Man

Abstract

Summary: The molecular classes of benzylpenicilloylspecific (BPO) antibodies detected in human sera by the presently described passive hemagglutination method (HA) were studied by mercaptoethanol (ME) degradation, ultracentrifugal fractionation in sucrose, and neutralization with monospecific rabbit anti-immunoglobulin sera. Sera whose HA titers were reduced to zero by ME treatment were shown to contain virtually only IgM antibodies. Sera whose HA titers were not reduced by ME were shown to contain mainly IgG antibodies, but small amounts of IgM and antibodies of other molecular classes were also present. The HA method was capable of detecting as little as 0.0003 µg/ml anti-benzylpenicilloyl (BPO) antibody protein in rabbit antisera and it may be more sensitive for human sera. By contrast, the passive cutaneous anaphylaxis (PCA) test in guinea pigs was 200-fold less sensitive for rabbit sera and 1500-fold for human sera. By means of this assay method, BPO-specific antibodies were detected in the sera of 97% of patients selected at random; most sera contained only IgM antibodies and 14% contained IgG antibodies in addition to IgM. BPO specificity of these antibodies was proved by hapten inhibition. Because of its specificity, sensitivity and simplicity, this method may be applicable to diverse immunologic studies.