Journals / Turkish Journal of Veterinary and Animal Sciences / 2020 / Cilt: 44 - Sayı: 3
Humoral immunity provided by a novel infectious bronchitis vaccine supplemented by bacterium-like particles (BLPs)
- Pages
- 534–541
- DOI
- —
Abstract
Infectious bronchitis (IB) is a notable disease of poultry flocks that results in economic loss. As a consequence of the presenceof various IB virus (IBV) serotypes, control strategies, such as vaccination, should be replaced by provide broad protective immunityagainst the disease to date. Gram-positive enhancer matrix particles, or so-called bacterium like particles (BLPs), obtained fromthe bacterium Lactococcus lactis (L. lactis), have demonstrated an adjuvancy effect by providing demanding mucosal and humoralimmune responses, as well as a protective cellular immunity whenever delivered admixed with a vaccine via intranasal or intraocularadministration. In this study, for the first time, attempts were made to investigate the impact of an IBV vaccine supplemented by variousdoses of BLPs on induced levels of humoral immunity against IB. For this purpose, increasing doses of derived BLPs (0, 0.15, 0.3, and 0.6mg dry weight per bird) were admixed with IBV live attenuated H120 serotype vaccine, and were delivered via ocular administration to4 equal groups of 10 specific pathogen-free (SPF) chickens in 4 groups: control, BLP1, BLP2, and BLP3, respectively. In addition, 10 SPFchickens that were not immunized comprised the Unvaccinated group. Blood was collected from 5 members of each group weekly for 35days. Levels of IgG antibodies in the sera were then assayed using ELISA. Weight gain and the feed conversion ratio of each group werealso recorded weekly. Finally, 3 birds from each group were necropsied to evaluate probable lesions. The best results were obtained in theBLP1 group, with IBV vaccination at a low dose of admixed BLPs boosted immediate anti-IBV humoral responses; however, the resultswere not significantly different from those of the Control group, but were still feasible enough for application in the field. In conclusion,BLPs could be a desirable adjuvant for IBV vaccines to increase immunity in chickens.