Evaluation of the immunization of camels with Brucella abortus vaccine (RB51) in Egypt.

Background: Brucellosis is a highly contagious zoonotic disease caused by an intracellular facultative microorganism termed Brucella spp. Control of brucellosis depends on test and slaughter policy as well as vaccination programs.
Aim: Estimation of the cell-mediated immunity (CMI) [total leukocytic count (TLC), phagocytic activity, phagocytic index, interleukin 6 (IL-6), and tumor necrosis factor-alpha (TNF-α)] in camels after vaccination with RB51 using real-time polymerase chain reaction (PCR).
Methods: A total of eight camels were grouped into two groups as follows: group (A): vaccinated with RB51 vaccine [1 dose/2 ml S/C (3 × 10 ¹⁰ CFU)] and group (B): control group. IL-6 and TNF-α were used for estimation of the CMI using real-time PCR on serum samples that were collected at 0, 7, 14, 21, 28, and 60 days after vaccination from each group. In addition, TLC, phagocytic activity, and phagocytic index were evaluated on heparinized blood samples at 0 and 60 days post-vaccination.
Results: RB51 vaccine provides a protective immune response which progressively increases from the first week to 60 days after vaccination. Moreover, the levels of TNF-α and IL-6 differed between camels in the vaccinated group.
Conclusion: Vaccination of camels with RB51 vaccine (with dose 3 × 10 ¹⁰ CFU) could induce good protective immune responses and this immunological response will be a good indication for a safe field vaccine that can be used for the control of camel brucellosis.
Competing Interests: The authors declare that they have no conflict of interest.