Association of transforming growth factor beta genes with quantitative trait loci for antibody response kinetics in...

Antibody responses (primary and secondary phases) were measured in an F2 population. The resource population was derived from grandsires of two highly inbred major histocompatibility complex (MHC)-congenic Fayoumi chicken lines (named M5.1 and M15.2) mated with highly inbred Leghorn G-B1 hens. Secondary phase parameters of maximum titres (Ymax) and time required to achieve Ymax (Tmax) were estimated from post-secondary titres by using a non-linear regression model. Associations of single nucleotide polymorphisms (SNP) in transforming growth factor beta2 (TGFB2), 3, and 4 genes with antibody response parameters were evaluated. Multiple immune response parameters were significantly associated with the TGFB2 gene primarily in the lineage of the M5.1 grandsire, suggesting that TGFB2 or linked genes affect antibody response in hens. Significant main effects of the three genes were mostly found in the lineage of the M5.1 grandsire. Significant two-way interactions on antibody response were primarily detected between TGFB3 and TGFB4 genes, and in the lineage of the M15.2 grandsire. Effects preferentially detectable in only one of the MHC-congenic lineages suggest that there was interaction between the MHC and TGFB genes. The characterized TGFB SNPs might be applied in marker-assisted selection to improve antibody production.