Safety and immunogenicity of Brucella abortus strain RB51 vaccine in cross bred cattle calves in India

Safety and immunogenicity of Brucella abortus RB51 vaccine has been evaluated in an organised dairy farm in India. All the cattle (n=29) vaccinated with strain RB51 'responded' to the vac- cine as demonstrated by iELISA using acetone killed strain RB51 antigen. The percentage responders at day 35, 60 and 90 post vaccination were 100%, 95% and 20%, respectively. Strain RB51 was able to elicit a good IFN-γ response from vaccinated animals. The post-vaccination time point analysis indicated that the cumu- lative IFN-γ response of whole blood from vaccinates stimulated with heat killed RB51 antigen was elicited in 80% of calves at 60 days post vaccination. Absence of strain RB51 in the secre- tions and excretion and lack of local or systemic reaction indicated the safety of the vaccine.