The potency testing of diphtheria and tetanus toxoids as determined by the induction of antibody in mice.

An antibody induction (AI) assay in mice has been developed for the potency testing of diphtheria and tetanus toxoids. A diphtheria-pertussis-tetanus served as a reference preparation so that both toxoids could be tested within the same experiment. Results have been compared with those obtained by the conventional lethal challenge tests in guinea pigs (diphtheria) and mice (tetanus). The potency values obtained in the AI tests reflected the differences in the toxoid content of the preparations. Being an economical method, the AI test can be recommended for the potency control of DPT vaccines subject to confirmation of the authors' observations by others.