Indirect elisa for potency testing of enterotoxaemia vaccine in sheep

The potency testing of Clostridium perfringens type D enterotoxaemia vaccine is currently performed with mouse neutralization test (MNT) to estimate the levels of epsilon antitoxin in the sera of sheep immunized with enterotoxaemia vaccine. The in vitro serological method like indirect ELISA has been developed for the determination of specific antibodies against epsilon toxin of Clostridium perfringens in the sera of sheep. The test showed high specificity and sensitivity. This ELISA procedure was used in addition to the routine MNT to determine immune response of sheep vaccinated with alum precipitated enterotoxaemia vaccine. The correlation coefficient between indirect ELISA and MNT was 0.98. The results indicated that indirect ELISA is suitable candidate to replace the MNT for potency testing of Clostridium perfringens type D vaccine.