Insights into the chicken bursa of fabricius response to Newcastle disease virus at 48 and 72 hours post-infection through RNA-seq

Newcastle disease virus (NDV) causes significant economic losses to the poultry industry worldwide. As a lymphoid organ, the bursa of Fabricius (BF) plays a pivotal role in destroying invading pathogens. Virulent NDV strains can cause rapid atrophy of the BF; however, there is limited knowledge regarding the BF innate immune response to NDV infection. In this study, we used the virulent NDV strain F48E9 to infect four-week-old chickens and found atrophy of the BF, with severe damage and high NDV viral loads after NDV infection in dying chickens. To better understand the interactions between the host and NDV, we compared the transcriptional profiles at 48 and 72 h following infection with the virulent NDV strain F48E9 using RNA-seq. We identified a total of 1498 differentially expressed genes (DEGs), which were enriched in a variety of biological processes and pathways according to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. The enriched pathways were associated with innate immune and inflammatory responses as well as metabolism-related signalling pathways. Excessive inflammatory and innate immune responses induced by the NDV strain may be related to severe BF damage. The global survey of changes in gene expression performed herein provides new insights into complicated molecular mechanisms underlying the interaction between NDV and chickens and will enable the use of new strategies to protect chickens against NDV.