Immunogenicity of a new, inactivated canine adenovirus type 2 vaccine for dogs

Abstract

We constructed a new canine adenovirus type 2 (CAV-2) vaccine candidate using the recently isolated Korean CAV-2 strain; we termed the vaccine APQA1701-40P and evaluated its safety and immunogenicity in dogs. Materials and Methods: To generate the anti-CAV-2 vaccine, APQA1701 was passaged 40 times in MDCK cells growing in medium containing 5 mM urea and the virus was inactivated using 0.05% (volume per volume) formaldehyde. Two vaccines were prepared by blending inactivated APQA1701-40P with two different adjuvants; both were intramuscularly injected (twice) into guinea pigs. The safety and immunogenicity of the Cabopol-adjuvanted vaccine were evaluated in seronegative dogs. The humoral responses elicited were measured using an indirect enzyme-linked immunosorbent assay (I-ELISA), and via a virus neutralization assay (VNA). Results: The new, inactivated CAV-2 vaccine strain, APQA1701-40P, lacked six amino acids of the E1b-19K protein. In guinea pigs, the Cabopol-adjuvanted vaccine afforded a slightly higher VNA titer and I-ELISA absorbance than an IMS gel-adjuvanted vaccine 4 weeks postvaccination (p>0.05). Dogs inoculated with the former vaccine developed a significantly higher immune titer than non-vaccinated dogs. Conclusion: The Cabopol-adjuvanted, inactivated CAV-2 vaccine was safe and induced a high VNA titer in dogs.

Genetic analysis of Canine adenovirus type 2 strains circulating in Turkey from past to present

“…In addition, it was observed that CAV-2 isolation and identification data, the reproduction time, and the CPE feature of the MDCK cell culture were similar to other researchers' results (Ditchfield et al 1962;116 Sarac F et al Genetic Chaturvedi et al 2008). Besides, the titers of CAV-2 were found 10 -6.0 , 10 -6,5 and 10 -6.75 TCID 50 /ml, which were among the titers obtained (10 -4.0 -10 -7.5 TCID 50 / ml) in other studies (Hu et al 2001;Chaturvedi et al 2008;Yang et al 2020).…”

“…HA1 is complementary to the genomic L chain at positions 770 to 791 in CAV-1 and 1387 to 1408 in CAV-2. HA2 is complementary to the genomic R chain at positions 1274 to 1253 in CAV-1 and 2413 to 2392 in CAV-2 (Yang et al 2020).…”

“…Most CAV-1 infections in dogs are subclinical, in some cases, the virus causes systemic disease (Mohammadi et al 2011). Canine adenovirus type-2 (CAV-2) mostly infects respiratory tissues and induces canine infectious laryngotracheitis in dogs, raccoons, foxes, wolves, and marine mammals (Hamir et al 1992;Hu et al 2001;Parthiban et al 2009;Yang et al 2020). It causes a localized respiratory disease in dogs and is one of the potential causes of the canine infectious respiratory disease complex (CIRDC) or kennel cough syndrome (an acute respiratory disease of canines).…”