Indian Journal of Poultry Science

Major histocompatibility complex (MHC) genes are known to be involved in host resistance to a variety of‘ antigens and pathogens. In this report, birds from three genetic groups viz. Bantam, Bantamised White leghorn (BWLH) and White Leghorn (WLH) were typed for the MHC class II (BLβ II family) alleles using polymerase chain reaction- sequence specific primer (PCR-SSP) and their association with immune response was evaluated. Genomic DNA was isolated from blood of 36 birds each of Bantam, BWLH and WLH. A 235 bp, exon-2 region of chicken MHC B-Lβ family was amplified using a set of degenerate primers. The products of the 1st round of amplification were subjected to PCR-SSP to amplify B₂, B₁₃, B₁₅, and B₂₁. The target sequences with the exception of B13 allele were amplified, producing 222 bp, 222 bp, 213 bp and 213 ^B19bp fragments. The study revealed nine genotypes viz., B₂B₂, B₂, B₂, B₁₅, B₁₅, B₁₅ B₁₉, B₁₉and B₂₁. Allelic ^B15^B19^B15^B21^B19^B19^B21^B21 and genotypic frequencies differed significantly among the three genetic groups.

Antibody titres against Newcastle disease virus (NDV) and Sheep RBC (SRBC) varied significantly among the three breed groups, sires, genotypes and sex. Correlations between antibody titres against NDV at different intervals were significant (P <0.05). However, a negative correlation between NDV and SRBC antibody titres were observed on 49th day of age. Genotype B15B19 showed highest antibody titres against NDV on 21st and 49th day of age followed by B₂B₁₉, B₂B₁₅ and B₂B₂. The study reflected the predominance of B₁₅ and B₁₉ alleles among Bantam and BWLH and WLH birds, which was consistent with antibody responses against the indicator antigens. It was suggestive of MHC class II (B-L) alleles B₁₅ and B₁₉’s association with antibody responses in birds.