Effects of Chicken MHC Haplotype on Resistance to Distantly-Related Infectious Bronchitis Viruses

The MHC B locus of chickens has been associated with resistance to different viral diseases. In previous work, we provided evidence that chicken lines expressing MHC haplotypes B2 and B19 presented relative resistance and susceptibility, respectively to a challenge with IBV M41. In the current study, we attempted to determine if those differences were true for genetically diverse IB viruses i.e. IBV M41 and ArkDPI. Clinical, pathological, molecular and immunological outcomes were compared. Our results showed subtle clinical and pathological differences among the two MHC chicken lines tested. Clinical differences were observed in respiratory signs at 2 dpi in M41 infected birds. Pathological differences were detected at 2 dpi in M41 infected viral load and at 6 dpi tracheal epithelial thickness in Ark DPI infected birds. Substantial differences were observed in antibody responses at 14 dpi. The transcriptome analysis showed that B19 chickens highly expressed genes related to inflammatory and innate immune ...