Prevention of Blackleg by an Immunogen of Clostridium chauvoei

Diseases in livestock caused by Clostridium spp. are of concern in Mexico. There are no good-quality vaccines against these infections, and for this reason several outbreaks have occurred in recent years. The objective of this work was to study the immunogenic capacity of a 156-kDa recombinant protein of Clostridium chauvoei that has shown 80% protection against this disease in guinea pigs. This immunogenic protein was cloned in the expression vector pBluescript and was used to immunize C. chauvoei-free bovine animals that were kept in an endemic area. Three experimental groups were studied. In group 1, 30 bovines were vaccinated by subcutaneous route with one dose of 350 μg/animal of the recombinant protein of 156 kDa. In group 2, 30 bovines were vaccinated with the same concentration of this protein plus aluminium hydroxide as adjuvant. Group 3 was vaccinated with a commercial bacterin by intramuscular route with a dose of 5 mL/animal. In each group, five animals were inoculated with saline solution and remained as controls without vaccination. Blood samples were obtained each month during a 6-month period. Serum samples were analyzed by agglutination test and Western blotting. The recombinant protein of 156 kDa was recognized by serum samples from all the animals in groups 1 and 2. Only two animals from group 3 recognized this protein. During the time of the experiment any cases of this disease were observed. However, other studies with a longer time or greater stress conditions that would favor occurrence of the disease would be required to confirm whether this immunogen is also protective in bovines.