An air-liquid interface model to investigate the niche preference of Campylobacter fetus

Abstract

Campylobacter fetus subspecies venerealis (Cfv) and Campylobacter fetus subspecies fetus (Cff) are pathogens primarily associated with reproductive problems in cattle and sheep. Cfv shows host specificity and tissue tropism, they are restricted to the genital tract of cattle, while Cff has a broad host distribution and can colonize different types of tissues. The virulence mechanisms underlying infection of Campylobacter fetus (C. fetus), and its hosts are poorly understood. The niche preference of C. fetus subspecies can be explained by comparing their ability to adhere to and invade host-specific epithelial cells. An air-liquid interface (ALI) model, which is a more physiologically relevant model than immortalized cell lines, was developed using primary bovine uterine epithelial to explore the niche preference of C. fetus. Due to the low viability of isolated bovine cervical cells, porcine cervical epithelial cells were used instead for infection assay to test different infection conditions. Brain Heart Infusion was identified as the most optimal medium for liquid culturing of C. fetus. The infection assay demonstrated the ability of Cff to adhere to porcine cervical epithelial cells. The highest adherence of cff cells was observed on epithelial cells infected with a multiplicity of infection of 50 after 1-hour incubation in BHI. These results show that ALI culture is a suitable model for studying the adherence of C. fetus. Therefore, further optimizing ALI models using bovine and ovine uterine epithelial cells is important to study C. fetus niche preference by comparing their adherence and invasion abilities.