Evaluation of oral immunization of sheep with Brucella Melitensis vaccine REV.1 in combination with Flagellin against a virulent Brucella melitensis 16 M strain

Abstract

In this work five vaccination protocols were prepared and applied these protocols in sheep. Serum samples were collected from each group at time points 25, 50, 77, 89, and 98 days post vaccination. The results revealed that humoral antibodies were detected in groups 3, 4 and 5 by using Rose Bengal test (RBT), Buffer Acidified Plate Antigen Test (BAPAT), and Tube Agglutination Test at 98 days, 77 days, and 77 days respectively, while for ELISA test revealed that were positive at 50, 89, 98, 98, and 98 days post vaccination in group 1, 2,3,4 and 5 respectively. Cell mediated immunity was evaluated by Lymphocyte Blastogenesis Assay Test and Brucellin test (Delayed Type Hyper Sensitivity Test). The results indicated that there were no significant differences in between mean of different groups at P ≤ 0.05, So for Skin Delayed Hyper Sensitivity test, Group 1 and group 6 were negative while Group 2, 3, 4 and 5 were positive. Conclusion, animals in Groups 3, 4 and 5 had humoral immune response and can be protected from abortion in pregnant ewes and prevent infection. In this work, we evaluated to potential of three doses reduced Rev.1 mixed with E. coli flagellin which induced protection without need of adjuvant against I/P Brucella melitensis challenge. Also these data suggest that flagellin proteins might induce protective immune responses and these proteins will be a good candidate for subunit vaccine against ovine brucellosis in sheep.