Stress-induced immunosuppression increases levels of certain circulating miRNAs and affects the immune response to an infectious bursal disease virus vaccine in chickens

Stress-induced immunosuppression can affect the immune effect of vaccine. However, the mechanism of stress induced immunosuppression affecting immune response to infectious bursal disease virus (IBDV) vaccine in chicken is still unclear. In this study, thirteen IBDV related circulating miRNAs were selected to study their expressions, possible functions and mechanisms in dexamethasone (Dex)-induced immunosuppressed chicken vaccinated with IBDV attenuated vaccine. The experiment aimed to explore the relationship between the expressions of IBDV related circulating miRNAs and stress-induced immunosuppression. The quantitative real-time PCR (qRT-PCR) results showed that Dex-induced immunosuppression could induce the differential expressions of the candidate serum circulating miRNAs, especially on the 2nd, 5th, 7th and 28th day after dexamethasone treatment. Dex-induced immunosuppression could affect the immune response to the IBDV vaccine, which was possibly achieved by partially regulating the differential expressions of the IBDV related circulating miRNAs. Bioinformatics analysis showed that the candidate miRNAs could regulate the immune function mainly through targeting genes (such as CREB1 and MAPK1) in TGF-beta and MAPK signaling pathways. This study can provide a preliminary reference for further studying the function and mechanism of circulating miRNAs in immune regulation.