Disfunção mitocondrial de macrófagos infectados com o vírus da bronquite infecciosa das galinhas e soroprevalência em aves não vacinadas

The macrophages play an important role in mediating innate immune responses induced by the Infectious Bronchitis Virus (IBV) and are protagonists in the connection between these responses and adaptive immunity. The IBV replicates in epithelial cells and macrophages resident in the respiratory organs of Gallus gallus domesticus; however, the mechanisms of generation of innate immune response against viral infection in these tissues, as well as, the morphological alterations of the avian macrophages, have not been fully characterized. Therefore, this study aimed to analyze the innate immune and humoral adaptive responses to IBV through the detection of mitochondrial dysfunction of HD11 avian macrophages infected by the Mass-41 viral strain and the investigation of IBV seroprevalence in flocks of non-vaccinated hosts. The investigations were performed with the use of Flow Cytometry and ELISA techniques, according to the technical instructions of the manufacturer. The most pronounced expression of changes in mononuclear phagocytic system cells was that of a high number of early apoptotic cells, in all postinfection periods. Viral infection was associated with mitochondrial membrane depolarization and the production of reactive oxygen species. In the serological test, a positivity was observed for Anti-IBV antibodies of 34% in the total of the studied subjects. This study demonstrated that viral replication leads to mitochondrial dysfunction of macrophages and, consequently, host immunosuppression. In addition, it showed the importance of vaccination, since the IBV directly affects the production and viability of the birds, which can lead to serious morbidity and mortality in the flock.