Protection of chickens against infectious bronchitis virus with a multivalent DNA vaccine and boosting with an inactivated vaccine

Abstract

The protective efficacy of DNA plasmids encoding avian infectious bronchitis virus (IBV) S1, N, or M protein was investigated in chickens. Chickens were inoculated monovalently (with plasmid pVAX1-16S1, pVAX1-16M, or pVAX1-16N alone) or multivalently (combination of the three different plasmids, pVAX1-16S1/M/N). A prime-boost immunization protocol against IBV was developed. Chickens were immunized with the multivalent DNA vaccine twice and then boosted with an inactivated vaccine once. Antibody titers of the chickens immunized with pVAX1-16S1/M/N were much higher than those of the monovalent groups (p < 0.01). A protective rate up to 90% was observed in the pVAX1-16S1/M/N group. The serum antibody titers in the prime-boost birds were significantly higher than those of the multivalent DNA vaccine group (p < 0.01) but not significantly different compared to the inactivated vaccine group at 49 days of age. Additionally, the prime-boost group also showed the highest level of IBV-specific cellular proliferation compared to the monovalent groups (p < 0.01) but no significant difference was found compared to the multivalent DNA vaccine group, and the prime-boost group completely protected from followed viral challenge.

DNA vaccination of poultry: The current status in 2015

“…In ovo DNA vaccination (with the VP243 antigen) priming followed by a booster vaccination with a killed IBDV vaccine resulted in a complete protection against an experimental protection [34]. DNA vaccination against infectious bronchitis virus (IBV) has also been widely studied [7,[37][38][39][40][41]. For example, between 60 and 90% of protection against experimental infections were achieved if plasmids encoding the S1, N and/or M proteins of the virus were inoculated [41].…”

“…DNA vaccination against infectious bronchitis virus (IBV) has also been widely studied [7,[37][38][39][40][41]. For example, between 60 and 90% of protection against experimental infections were achieved if plasmids encoding the S1, N and/or M proteins of the virus were inoculated [41]. In ducks, the most widely studied virus is duck hepatitis B virus (DHBV) as a model of chronic human hepatitis infection [42][43][44][45][46][47].…”

“…In chickens, for example, the combination of IBDV VP2, VP4 and VP3 induced significantly higher protective immune responses than VP2 alone [9,29,30,32]. Likewise, the synergistic effect of two or more vaccine antigens enhanced vaccine efficacy against IBV [41], avian reovirus [92], avian Pasteurella multocida [69] or CAV [93] in chickens. This was also the case for the DNA vaccine against duck enteritis virus [94].…”

“…The stimulated immune cells were rarely characterized. It has been shown that CD8 + and CD4 + T cells proliferated in chickens [27,38,41] and ducks [94].…”

Recombinant duck enteritis viruses expressing major structural proteins of the infectious bronchitis virus provide protection against infectious bronchitis in chickens

“…Genetically engineered vaccines present an alternative to inactivated and attenuated vaccines. In previous studies, a multivalent DNA vaccine expressing S1, N, and M conferred 85% protection , while a multivalent DNA vaccine combined with an inactivated vaccine booster conferred complete protection (Yan et al, 2013). In addition, a recombinant Newcastle disease virus expressing the S2 protein of IBV was shown to provide broad protection against IBV challenge (Toro et al, 2014).…”