The immunological response of RB51 vaccinated buffalo calves using brucella periplasmic proteins as ELISA antigen
Immune status of RB51 vaccinated buffaloes was evaluated using tube agglutination test (TAT) and ELISA, using both periplasmic protein antigen (PPA) and lipopolysaccharide antigen (LPS). For this purpose, three groups of buffalo calves were used. The first one received S19 vaccine subcutaneously; the second was vaccinated once subcutaneously with RB51 vaccine. The third (control) group was injected similarly with sterile saline. Concerning the S19 vaccinated group, significant TAT titers were seen 1 week post vaccination (WPV) till the maximum at the 2nd WPV. After that it was gradually decreased till the 7 WPV, then sharply before it completely disappeared at the 13 WPV. On the other hand, the LPS-ELISA showed an antibody titer as early as one WPV reached its peak at 2 WPV and persisted steadily till the 6th WPV and decreased slowly when it reached minimal level at the 16 WPV till the end of the experiment. While in RB51 vaccinated buffalo calves using the PPA-ELISA, the antibody titer began and reach the maximum as early as the first WPV, still steady till 2 WPV, fluctuating till the 6th WPV, then dropped sharply when it disappeared at 11WPV till the end of the experiment.
Key words: Brucella, buffaloes, ELISA, lipopolysaccharide (LPS), periplasmic proteins, RB51, S19, tube agglutination test (TAT).