Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/24/2012
Publication Date: 6/24/2012
Citation: Xie, Q., Chang, S., Ernst, C.W., Dunn, J.R., Song, J., Zhang, H. 2012. Differential genetic variation of chickens and MD vaccine protective efficacy [abstract]. 9th International Symposium on Marek's Disease and Avian Herpesviruses, June 24-28, 2012, Freie Universitat Berlin. p.36. Interpretive Summary:
Technical Abstract: Vaccine protective efficacy is determined by multiple factors including host genetics, the type of vaccine, vaccine dosage, the virulence and dose of challenging viruses, and the interval between vaccination and viral challenge. Studies on human immune responses to vaccinations suggest host genetic variability has a strong effect and involves both genes within and outside of the major histocompatibility complex (MHC). Using chickens from two highly inbred and specific pathogen free lines (63 and 72) sharing a common MHC (B*2) haplotype in challenge trials, striking differences in protective efficacy were observed when vaccinated with HVT or CVI988/Rispens at either 500PFU/bird or at a commercial dosage. Genome-Wide SNP scan identified 14,925 SNPs mainly residing on chromosomes 1-15, 17-28 and Z, out of 57,636 SNPs, that differ between the two lines. DNA methylation level, an epigenetic factor, was also found to differ between the two lines at promoter regions of genes with hypomethylation, intermediate methylation, or hypermethylation levels. Differential gene expression post vaccination between the two lines will also be discussed. A better understanding of the roles of host genetics in immunological challenge will serve as the touchstone for rational design and development of novel safe and effective vaccines.