Efficacy of an adenovirus-vectored foot-and-mouth disease virus serotype A subunit vaccine in cattle using a direct contact transmission model

• Published in: BMC veterinary research 2018-08, Vol.14 (1), p.254-9, Article 254
• Main Authors: Neilan, John G, Schutta, Christopher, Barrera, José, Pisano, Melia, Zsak, Laszlo, Hartwig, Ethan, Rasmussen, Max V, Kamicker, Barbara J, Ettyreddy, Damodar, Brough, Douglas E, Butman, Bryan T, Brake, David A
• Format: Article
• Language: English
• Subjects: Adenoviruses; Adenoviruses, Human - genetics; Animals; Antibodies, Viral - blood; Bovidae; Capsid Proteins - genetics; Cattle; Cattle Diseases - immunology; Cattle Diseases - prevention & control; Cattle Diseases - virology; Clinical trials; Computer simulation; Disease transmission; DIVA; Epidemics; Exposure; FMDV A24/Cruzeiro/BRA/55; Foot & mouth disease; Foot-and-Mouth Disease - immunology; Foot-and-Mouth Disease - prevention & control; Foot-and-Mouth Disease - virology; Foot-and-mouth disease virus; Foot-and-Mouth Disease Virus - immunology; Hogs; Homology; Male; Neck; Nonstructural proteins; Outbreaks; Proteins; Replication-deficient human adenovirus vectored vaccine; Replication-deficient human adenovirusvectored vaccine; Serogroup; Vaccination; Vaccine efficacy; Vaccines; Vaccines, Subunit - immunology; Veterinary Sciences; Viral Nonstructural Proteins - immunology; Viral Vaccines - immunology; Viruses
• ISSN: 1746-6148; 1746-6148
• DOI: 10.1186/s12917-018-1582-1

A direct contact transmission challenge model was used to simulate natural foot-and-mouth disease virus (FMDV) spread from FMDV A24/Cruzeiro/BRA/55 infected 'seeder' steers to naïve or vaccinated steers previously immunized with a replication-deficient human adenovirus-vectored FMDV A24/Cruzeiro/BRA/55 capsid-based subunit vaccine (AdtA24). In two independent vaccine efficacy trials, AdtA24 was administered once intramuscularly in the neck 7 days prior to contact with FMDV A24/Cruzeiro/BRA/55-infected seeder steers. In Efficacy Study 1, we evaluated three doses of AdtA24 to estimate the 50%/90% bovine protective dose (BPD ) for prevention of clinical FMD. In vaccinated, contact-challenged steers, the BPD was 3.1 × 10 / 5.5 × 10 AdtA24 particles formulated without adjuvant. In Efficacy Study 2, steers vaccinated with 5 × 10 AdtA24 particles, exposed to FMDV A24/Cruzeiro/BRA/55-infected seeder steers, did not develop clinical FMD or transmit FMDV to other vaccinated or naïve, non-vaccinated steers. In contrast, naïve, non-vaccinated steers that were subsequently exposed to FMDV A24/Cruzeiro/BRA/55-infected seeder steers developed clinical FMD and transmitted FMDV by contact to additional naïve, non-vaccinated steers. The AdtA24 vaccine differentiated infected from vaccinated animals (DIVA) because no antibodies to FMDV nonstructural proteins were detected prior to FMDV exposure. A single dose of the AdtA24 non-adjuvanted vaccine conferred protection against clinical FMD at 7 days post-vaccination following direct contact transmission from FMDV-infected, naïve, non-vaccinated steers. The AdtA24 vaccine was effective in preventing FMDV transmission from homologous challenged, contact-exposed, AdtA24-vaccinated, protected steers to co-mingled, susceptible steers, suggesting that the vaccine may be beneficial in reducing both the magnitude and duration of a FMDV outbreak in a commercial cattle production setting.