ARS | Publication request: Non-MHC genomic variation affecting Marek’s disease resistance and vaccine protective efficiency

Submitted to: Annual International Plant & Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: December 23, 2008
Publication Date: January 9, 2009
Citation: Chang, S., Dunn, J.R., Heidari, M., Lee, L.F., Song, J., Dodgson, J., Ding, Z., Zhang, H. 2009. Non-MHC Genomic Variation Affecting Marek’s Disease Resistance and Vaccine Protective Efficiency [abstract]. International Plant and Animal Genome XVII Conference, January 9-14, 2009, San Diego, California. p. 526.

Technical Abstract: Marek’s disease (MD) is a lymphoproliferative disease of the domestic chicken caused by a highly infectious, oncogenic herpesvirus commonly referred to as Marek’s disease virus (MDV). MD has been controlled by vaccination with non-oncogenic turkey herpesvirus (HVT), non-oncogenic chicken herpesvirus (serotype 2 SB-1 MDV), or attenuated oncogenic herpesvirus (CVI988/Rispens) in the field. Strategies, such as genetic resistance, to augment current control scheme have been actively investigated. Reported studies provide compelling evidence that MHC plays an important role in resistance to MD. This report presents the MD resistance of a series of 19 recombinant congenic strains (RCS) and their progenitor lines of chickens sharing the same B2 MHC haplotype and their responses to three kinds of vaccines followed by challenge of a vv+ strain of MDV. Randomly sampled day-old chicks from each of the RCS and progenitor lines were vaccinated either with HVT, CVI988/Rispens, or rMd5-Delta-Meq or not vaccinated and challenged at 5 days with MDV. Through necropsy chickens that died during or were terminated at the end of the experiment were examined for nerve lesions and/or gross tumors. MD incidences of 28.6% and 100% were observed in the MD resistant and susceptible progenitor lines (63, 72), respectively, for the unvaccinated group. The MD incidences among the 19 RCS ranged from 44.4-100% for the same treatment suggesting significant variation of MD resistance among the series of RCS. Vaccine protection indexes varied greatly among chicken lines and vaccine treatments. These results taken together indicate that line-specific-non-MHC-genome variation also significantly affects vaccine efficacy.