Analysis of the early immune response to infection by Infectious Bursal Disease Virus (IBDV) in chickens differing in their resistance to the disease

Chicken whole genome gene expression arrays were used to analyse the host response to infection by Infectious Bursal Disease Virus (IBDV). Spleen and bursal tissue were examined from control and infected birds at 2, 3 and 4 days post-infection from two lines that differ in their resistance to IBDV infection. The host response was evaluated over this period and differences between susceptible and resistant chicken lines were examined. Anti-viral genes, including IFNA, IFNG, MX1, IFITM1, IFITM3 and IFITM5 were up-regulated in response to infection. Evaluation of this gene expression data has allowed us to predicted several genes as candidates for involvement in resistance to IBDV.

IMPORTANCE: Infectious bursal disease (IBD) is of economic importance to the poultry industry and thus is also important for food security. Vaccines are available but field strains of the virus are of increasing virulence. There is thus an urgent need to explore new control solutions, one of which would be to breed birds with greater resistance to IBD. A goal which is perhaps uniquely achievable with poultry, of all farm animal species, as the genetics of 85% of the 60 billion chickens produced worldwide each year is under the control of essentially two breeding companies. This is the most comprehensive study to try to identify global transcriptomic differences in the target organ of the virus between chicken lines that differ in resistance, and to predict candidate resistance genes.