Antigens in penicillin allergy. III. Antigen and antibody levels in mice treated with pure and contaminated penicillins.

Using a radioimmunoassay, it was shown that commercially available ampicillin preparations often contain penicilloylated high molecular weight impurities. These possess immunological activities and stimulate penicilloyl-specific antibody formation in mice treated according to a therapeutic schedule. Using purified and experimentally contaminated preparations it was also found that exposure of the animals to Escherichia coli and Bordetella pertussis bacteria could increase the antibody formation to small amounts of impurities. In addition, penicilloylated antigen could be recorded in serum from treated animals. The antigen formed by penicilloylation in vivo, however, was very weak and did not induce much antibody formation when injected together with Freund's adjuvant in mice or rabbits.