Stress-induced immunosuppression affecting immune response to Newcastle disease virus vaccine through "miR-155-CTLA-4"pathway in chickens

MiR-155 and CTLA-4 are important factors involved in the regulation of immune function. However, there is no report about their involvement in function regulation of stress-induced immunosuppression affecting immune response. In this study, the chicken model of stress-induced immunosuppression affecting immune response (simulation with dexamethasone and immunization with Newcastle disease virus (NDV) attenuated vaccine) was established, then the expression characteristics of miR-155 and CTLA-4 gene were analyzed at several key time points during the processes of stress-induced immunosuppression affecting NDV vaccine immune response at serum and tissue levels. The results showed that miR-155 and CTLA-4 were the key factors involved in stress-induced immunosuppression and NDV immune response, whose functions involved in the regulation of immune function were different in different tissues and time points, and 2 day post immunization (dpi), 5dpi and 21dpi were the possible key regulatory time points. CTLA-4, the target gene of miR-155, had significant game regulation relationships between them in various tissues, such as bursa of Fabricius, thymus and liver, indicating that miR-155-CTLA-4 pathway was one of the main mechanisms of their involvement in the regulations of stress -induced immunosuppression affecting NDV immune response. This study can lay the foundation for in-depth exploration of miR-155-CTLA-4 pathway involved in the regulation of immune function.