Campylobacter fetus is Internalized by Bovine Endometrial Epithelial Cells

Campylobacter fetus is an important venereal pathogen of cattle that causes infertility and abortions. It is transmitted during mating, and it travels from the vagina to the uterus; therefore, an important cell type that interacts with C. fetus are endometrial epithelial cells. Several virulence factors have been identified in the genome of C. fetus, such as adhesins, secretion systems, and antiphagocytic layers, but their expression is unknown. The ability of C. fetus to invade human epithelial cells has been demonstrated, but the ability of this microorganism to infect bovine endometrial epithelial cells has not been demonstrated. Bovine endometrial epithelial cells were isolated and challenged with C. fetus. The presence of C. fetus inside the endometrial epithelial cells was confirmed by the confocal immunofluorescence. C. fetus was not internalized when actin polymerization was disturbed, suggesting cytoskeleton participation in an internalization mechanism. To evaluate the intracellular survival of C. fetus, a gentamicin protection assay was performed. Although C. fetus was able to invade epithelial cells, the results showed that it did not have the capacity to survive in the intracellular environment. This study reports for the first time, the ability of C. fetus to invade bovine endometrial epithelial cells, and actin participation in this phenomenon.