The Bactericidal Action of Bovine Blood for Brucella and Its Possible Significance

Abstract

Several factors influenced the results of an in vitro test for measuring the bactericidal action of bovine blood for Brucella. Blood plasma from normal calves and cows possesses a complex which kills large numbers of B. abortus in vitro. Serum possesses the same property, but to a lesser extent. The bactericidal complex does not make its appearance in calf blood to any extent until after the ingestion of colostrum. Blood plasma from cows infected with B. abortus possesses a property which inhibits the killing action of the bactericidal complex for Brucella. Brucella-infected cows may be detected and distinguished from those not infected by making use of differences shown in the bactericidal action of their plasma for Brucella. The serial dilution method reveals greater differences in the bacteria-growth-inhibiting action of plasma from normal and Brucella-immune cows. Such differences suggest that specific bactericidal antibodies, if present in sufficient conc. play an important role in the protection of cattle against brucellosis.