The MHC of a broiler chicken line: serology, B-G genotypes, and B-F/B-LB sequences

Abstract

Although the major histocompatibility complex of chickens (encoded in the B complex) has been studied for a number of years, almost all work has focused on the White Leghorn breed. Broiler (meat-type) chickens were derived from other breeds, including Cornish and Plymouth Rock. It was our hypothesis that new B haplotypes, not previously identified in White Leghorns, might be present in lines of broiler chickens. Furthermore, alloantisera used to identify B serotypes in Leghorn lines reportedly do not work well outside the line in which they were raised, with the result that broiler B haplotypes have not been incorporated into the universal nomenclature system. Our approach was to use a panel of B alloantisera produced to identify B serotypes within a commercial broiler breeder line (designated line A). B homozygotes identified serologically were compared by B-G genotyping using restriction fragment length polymorphism analysis. Furthermore, reverse transcription-polymerase chain reaction was used to amplify variable domains of expressed B-LB and B-F genes of homozygotes of most of the B serotypes in Line A, followed by cloning and nucleotide sequence determination. Comparison of B-LB and B-F sequences with standard Leghorn haplotypes demonstrated the existence of new alleles of B-L and B-F in a broiler breeder line, as well as the presence of alleles previously identified in Leghorns. In some cases, Leghorn-type alleles were in linkage with different B-G alleles in the broiler line than the common haplotypic associations found in Leghorn lines.

Serological Screening for MHC (B)-Polymorphism in Indigenous Chickens

“…Thus,`standard' haplotypes are almost all derived from the White Leghorn. However, preliminary typing of other (indigenous) breeds of chickens, and of wild chickens, indicates the existence of a much wider spectrum of allomorphs (Simonsen et al, 1982) and reveals new alleles, often with distinct haplotypes (Hepkema et al, 1991;Briles et al, 1993;Li et al, 1999;Livant et al, 2001). Since each class of MHC genes is a potential candidate for a role in disease resistance (Nordskog et al, 1987;Lamont, 1998a) and immune response (Fulton et al, 1996), knowledge of the B system of poultry should not be limited to White Leghorns.…”

Retrospective evidence that the MHC (B haplotype) of chickens influences genetic resistance to attenuated infectious bronchitis vaccine strains in chickens

“…Alternatively, the current data indicate that one could select for chickens with the B*15 haplotype to increase resistance to IBV. Indeed, the resistant B*15 haplotype is prevalent in both egg-laying and broiler chicken strains (Briles & Briles, 1982;Li et al, 1999). However, it is unlikely selection for a resistant B haplotype (e.g.…”

Major histocompatibility complex effect on cellulitis among different chicken lines

“…It was shown by Li et al (1999) . For the purpose of the present report, the standard Leghorn nomenclature will be used in place of those two designations.…”