In vitro adherence and invasion of primary chicken oviduct epithelial cells by Gallibacterium anatis

Gallibacterium anatis (G. anatis) has been suggested to have a causal role in salpingitis and peritonitis in egg-laying chickens, leading to decreased egg production and increased mortality worldwide. Adherence and invasion of epithelial cells are thought to play a role in the pathogenesis of G. anatis infection. The purpose of this article was to study adherence and invasion of G. anatis using two G. anatis strains of different virulence (Yu-PDS-RZ-1-SLG strain, highly virulent and F149^T strain, non-virulent) via infection of the primary chicken oviduct epithelial cells (PCOECs).The results showed that Yu-PDS-RZ-1 -SLG strain was able to attach to PCOECs at higher levels than that of F149^T strain, but no invasion was observed with either strain. However, cell debris and cell apoptosis were observed after being exposed to G. anatis Yu-PDS-RZ-1-SLG for 90min, whereas G. anatis F149^T did not cause cell damage, and adherence was prevented by trypsin treatment of bacterial cells. Cytokines were detected by ELISA after infection, and the results showed that the expression of IL-6, TNF-α, and IFN-γ levels was higher in virulent strain infection than that of the avirulent group. Results also indicated that the highly virulent strain G. anatis displayed an increased level of adherence. Changes in cytokine profiles in this study suggested that the production of cytokines might influence the microenvironment of oviduct and promote adherence, serving as a possible mechanism inducing cell damage.