Submitted to: International Marek's Disease Symposium Abstracts and Proceedings
Publication Type: Proceedings
Publication Acceptance Date: September 7, 1996
Publication Date: N/A
Technical Abstract: Chickens have recently been shown to possess class I and class II Mhc-like genes, collectively termed the Rfp-Y haplotype, that assort independent of the B-complex. Cornell lines N and P, selected for resistance or susceptibility, respectively, to Marek's disease (MD) possess different Rfp-Y haplotypes, i.e. N has Y**5, Y**7 and **Y8, whereas P has Y**5, Y**8, and Y**9. In addition, the ADOL inbred lines 63 and 72, resistant or susceptible to MD, respectively, each contains an additional unique Rfp-Y haplotype (tentatively termed Y**11 and Y**12). The effect of Rfp-Y haplotype on MD was studied in chickens produced by Rfp-Y heterozygous parents in lines N, P, a backcross mating of those lines, and a 72X63 F2 mating. The chicks were assessed for B-genotype by blood-typing, and for Rfp-Y genotype by RFLP analysis using Bam HI enzyme and a Rfp-Y LBIII probe, or Taq I enzyme and a B-FIV probe. Chicks were challenged with 2,000 pfu of JM virus at 1-2 weeks of age and termination was at 10 weeks. The Rfp-Y genes had no significant influence on MD tumors or MD viremia in N, P, or P x (NxP) chicks, whereas the B haplotype had major influences on these traits in the backcross chicks. Moreover, the Rfp-Y haplotype influenced neither MD viremia nor tumor development in the 72x63 F2 chickens. We conclude that MD resistance is not significantly influenced by the Rfp-Y haplotype in two resistant x susceptible strain crosses and that any effects of the Rfp-Y loci must be minuscule compared to effects conferred by the Mhc B haplotype.