Evaluation of protective efficacy of three novel H3N2 canine influenza vaccines

Abstract

Canine influenza virus (CIV) has the potential risk to spread in different areas and dog types. Thus, there is a growing need to develop an effective vaccine to control CIV disease. Here, we developed three vaccine candidates: 1) a recombinant pVAX1 vector expressing H3N2 CIV hemagglutinin (pVAX1-HA); 2) a live attenuated canine adenovirus type 2 expressing H3N2 CIV hemagglutinin (rCAV2-HA); and 3) an inactivated H3N2 CIV (A/canine/Guangdong/01/2006 (H3N2)). Mice received an initial intramuscular immunization that followed two booster injections at 2 and 4 weeks post-vaccination (wpv). The splenic lymphocytes were collected to assess the immune responses at 6 wpv. The protective efficacy was evaluated by challenging H3N2 CIV after vaccination (at 6 wpv). Our results demonstrated that all three vaccine candidates elicited cytokine and antibody responses in mice. The rCAV2-HA vaccine and the inactivated vaccine generated efficient protective efficacy in mice, whereas limited protection was provided by the pVAX1-HA DNA vaccine. Therefore, both the rCAV2-HA live recombinant virus and the inactivated CIV could be used as potential novel vaccines against H3N2CIV. This study provides guidance for choosing the most appropriate vaccine for the prevention and control of CIV disease.

Establishment of a Simple and Efficient Reverse Genetics System for Canine Adenoviruses Using Bacterial Artificial Chromosomes

“…Our observation that the E1-deleted CAdV2 mutant replicated less efficiently than the WT virus in MDCK cells provides a possibility that this mutant may be attenuated in vivo, suggesting its potential as a live vaccine against CAdV infections. Therefore, this mutant-based recombinant constructs containing protective antigens of other pathogens such as rabies virus, canine distemper virus, canine influenza virus, etc., can be applied to multivalent vaccine strategy for canid animals, as approached in previous studies [ 16 , 40 , 41 ].…”

Vaccination with an inactivated canine influenza H3N2 virus vaccine is safe and elicits an immune response in cats

“…These findings are consistent with other studies demonstrating an induction of HAI antibody titers following immunization with H3N2 CIV vaccine. 13,14 Nonetheless, controlled experimental challenge with a virulent H3N2 CIV strain is necessary to test the protective efficacy of this inactivated H3N2 CIV vaccine in cats.…”