|FERREIRA, HELENA - Orise Fellow|
Submitted to: Vaccines
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2021
Publication Date: 2/21/2021
Citation: Ferreira, H.L., Miller, P.J., Suarez, D.L. 2021. Protection against different genotypes of Newcastle disease viruses (NDV) afforded by an adenovirus-vectored fusion protein and live NDV vaccines in chickens. Vaccines. 9(2):182. https://doi.org/10.3390/vaccines9020182.
Interpretive Summary: Newcastle disease virus is a major poultry pathogen world wide and in susceptible chickens can cause high morbidity and mortality. Vaccination is commonly used to protect poultry from the disease. Previous studies have shown that an immune response expressing the hemagglutinin-neuraminidase (HN) or fusion proteins can be protective. We developed an adenovirus vectored vaccine that expresses the fusion protein from a California 2002 influenza virus. Using this vaccine birds were vaccinated and then challenged with 3 different virulent Newcastle disease viruses. The best protection was seen when the fusion protein from the vaccine closely matched the fusion vaccine in the challenge virus. Some protection was still observed with the other two challenge viruses. The recommendation was that matching the vaccine to the field strain as closely as possible will provide better protection.
Technical Abstract: The efficacy of an adenovirus-vectored Newcastle disease virus (NDV) vaccine expressing the fusion (F) NDV protein (adeno-F) was evaluated against challenges with virulent heterologous and homologous NDV strains to the F protein. In a preliminary study, two different doses (low and high) of adeno-F were tested against a virulent NDV strain containing the homologous NDV F protein, CA02. In a second study, at three weeks post-vaccination, the efficacy of the high dose of adenoF was compared to a live attenuated NDV vaccine strain (LaSota) against three antigenically distinct virulent NDV challenge strains, one homologous (CA02) and two heterologous (TZ12, EG14) to F in the vectored vaccine. In both experiments, clinical signs, mortality, virus shedding, and humoral response were evaluated. In the first experiment, the survival rates from birds vaccinated with adeno-F at a high and low dose were 100% and 25%, respectively. In the second experiment, birds vaccinated with the high dose of adeno-F had a survival rate of 80%, 75%, and 65% after challenge with the CA02, TZ12, and EG14 viruses, respectively. All of the LaSota-vaccinated birds survived post-challenge no matter the NDV challenge strain. High antibody titers were detected after vaccination with LaSota by HI and ELISA tests. The majority of adeno-F-vaccinated birds had detectable antibodies using the ELISA test, but not using the HI test, before the challenge. The data show that both the similarity of the F protein of the adeno-F vaccine to the challenge virus and the adenoF vaccination dose affect the efficacy of an adenovirus-vectored NDV vaccine against a virulent NDV challenge.