Bovine enterotoxaemia caused by Clostridium perfringens type A most often presents as a sudden death syndrome with necro-hemorrhagic small intestinal lesions in suckling calves and veal calves (Muylaert et al., 2010). Alpha toxin, in synergy with perfringolysin O, has recently been proposed as an essential factor for the induction of enterotoxaemia in calves (Verherstraeten et al., 2013). Due to the rapid progress of the disease, preventive measures such as vaccination are of crucial importance to control enterotoxaemia.
In this study, we compared the protective potential of a C. perfringens crude toxin preparation and the formalin-inactivated counterpart. Subcutaneous vaccination of calves with either of these preparations resulted in a strong antibody response against alpha toxin and perfringolysin O. However, only antibodies produced by animals immunized with native, non-inactivated toxin preparations were able to inhibit C. perfringens induced cytotoxicity and offered protection against bovine enterotoxaemia in a previously validated intestinal loop model (Valgaeren et al., 2013). These results show a discrepancy between the antibody titers raised against formalin-inactivated C. perfringens toxins and the protective capacity. Inactivation using formalin may modify crucial epitopes of the toxins, eliminating the toxin-neutralizing capacity of the evoked antibodies. However, vaccination with C. perfringens toxins may be valuable to protect calves from enterotoxaemia and other inactivation methods need to be explored
