Effects of chicken interferon Gamma on Newcastle disease virus vaccine immunogenicity

Authors: CARDENAS-GARCIA, STIVALIS - University Of Georgia; DUNWOODY, ROBERT - Mercer University; MARCANO, VALERIE - University Of Georgia; DIEL, DIEGO - South Dakota State University; WILLIAMS, ROBERT - University Of Georgia; GOGAL JR., ROBERT - University Of Georgia; BROWN, CORRIE - University Of Georgia; Miller, Patti; Afonso, Claudio

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/28/2016
Publication Date: 7/13/2016
Publication URL: https://handle.nal.usda.gov/10113/62832
Citation: Cardenas-Garcia, S., Dunwoody, R.P., Marcano, V., Diel, D.G., Williams, R.J., Gogal Jr., R.M., Brown, C.C., Miller, P.J., Afonso, C.L. 2016. Effects of chicken interferon Gamma on Newcastle disease virus vaccine immunogenicity. PLoS One. 11(7):e0159153. doi:10.1371/journal.pone.0159153.

Interpretive Summary: Newcastle disease (ND) is a disease of birds and a big concern for the poultry industry because it has the ability to cause high rates of disease and death leading to big economic losses and export restrictions . Newcastle disease is caused by Newcastle Disease virus, a highly contagious agent that infects multiple species of birds. Around the world disease and mortality is prevented with vaccines. Scientists know that some substances, known as adjuvants, are added to the vaccines to improve vaccination success. Over the last twenty years scientists have been studying proteins known as cytokines that are produced when humans or animals are infected with bacteria or viruses. One of those proteins interferon gamma has been suggested to be a good adjuvant. Here we looked at vaccine performance when a chicken interferon gamma was used as an adjuvant with three types of ND vaccines (DNA plasmid based, live and inactivated Newcastle disease virus). In all three systems, the ability of the ND vaccine to work and protect the chicken from disease was either made worse or not improved compared to the same vaccines without the cytokine adjuvant.

Technical Abstract: More effective vaccines are needed to control avian diseases. The use of chicken interferon gamma (chIFN') during vaccination is a potentially important but controversial approach that may improve the immune response to antigens. In the present study, three different systems to co-deliver chIFN' with Newcastle disease virus (NDV) antigens were evaluated for their ability to enhance the avian immune response and their protective capacity upon challenge with virulent NDV. These systems consisted of: 1) a DNA vaccine expressing the Newcastle disease virus fusion (F) protein co-administered with a vector expressing the chIFN' gene for in ovo and booster vaccination, 2) a recombinant Newcastle disease virus expressing the chIFN' gene rZJ1*L/IFN') used as a live vaccine delivered in ovo and into juvenile chickens, and 3) the same rZJ1*L/IFN' virus used as an inactivated vaccine for juvenile chickens. Co-administration of chIFN' with a DNA vaccine expressing the F protein resulted in higher levels of morbidity and mortality, and higher amounts of virulent virus shed after challenge when compared to the group that did not receive chIFN'. The live vaccine system co-delivering chIFN' did not enhanced post-vaccination antibody response, nor improved survival after hatch, when administered in ovo, and did not affect survival after challenge when administered to juvenile chickens. The low dose of the inactivated vaccine co-delivering active chIFN' induced lower antibody titers than the groups that did not receive the cytokine. The high dose of this vaccine did not increase the antibody titers or antigen-specific memory response, and did not reduce the amount of challenge virus shed or mortality after challenge. In summary, regardless of the delivery system, chIFN', when administered simultaneously with the vaccine antigen, did not enhance Newcastle disease virus vaccine immunogenicity.