[Development and prevalidation of alternative methods for the potency testing of C. perfringens vaccines]

The requirements for the quality control of C. perfringens vaccines for veterinary use are described in the monograph 363 of the European Pharmacopoeia (Ph. Eur.). In the current used potency test neutralising antibodies against C. perfringens beta- and epsilontoxin are determined in a mouse neutralisation test (MNT). Two ELISA methods were developed for the replacement of the MNT. Both methods use monoclonal antibodies to determine the quantity of specific antibodies against beta toxin (Capture-ELISA) and epsilon toxin (Competitive-ELISA) in vitro. In parallel to the routine batch potency test in mice, the beta- and epsilonantitoxin levels in 523 samples were estimated in the ELISA procedures. A high specificity and a good reproducibility are evident for both test systems. An interlaboratory prevalidation study was carried out to evaluate the relevance and the transferability of the ELISA procedures. It is concluded that both ELISA systems seems to be suitable alternative methods for assessing the potency of beta- and epsilontoxoid in batches of vaccines for veterinary use.