Studies of histocompatibility and immune response of chickens selected for resistance and susceptibility to Marek's disease

Two sets (four lines) of chickens, lines 7 and 6 and lines P and N, the former of each set susceptible and the latter resistant to Marek's disease, were examined for their relative histocompatibility and immunocompetence. Results from the in vivo graft-versus-host response splenomegaly assay, and graft-versus-host chorioallantoic membrane pock formation assay confirmed the within-line, B-locus homozygosity of chickens of lines 7, 6, and N and the heterozygosity of line-P chickens. These assays further confirmed that line-7 and line-6 chickens share identical alleles at the major histocompatibility locus. The capacity of the lines of chickens to elicit specific cell-mediated immune lysis as measured by the release of chromium 51 generally agreed with the in vivo graft-versus-host responses. These data demonstrate that the51Cr-release assay is a reliable measure of histocompatibility within the avian system.