S. aureus and E. coli induce IL-32 gene expression to different extents during infection of bovine mammary gland epithelial cells
Résumé
Introduction: While the role of many cytokines during infection is known, the implication of recently discovered cytokines is not well defined. The involvement of recently described
interleukin-32 in infectious mastitis, caused by two prevalent mastitis pathogens, Staphylococcus aureus and Escherichia coli, has not been investigated so far and we present initial
results.
Material and Methods: Two bovine mammary gland epithelial cells lines (BME-UV and PS) were infected with bovine infectious mastitis organisms E. coli or S. aureus. Using RT- qPCR
the kinetics of IL-32, IL-6 and IL-8 gene expression was determined.
Results: E. coli induces a weak IL-6 expression in BME-UV and a strong IL-6 expression in PS cells, while a faint IL-6 expression was observed during S. aureus infection in both cell
lines. IL-8 expression was detected during the exposure to both pathogens with the strongest signal in E. coli-infected PS cells. Regarding IL-32 expression, different responses were
observed in cells exposed to E. coli and S. aureus strains: while IL-32 expression was increased in both cell lines infected with E. coli, there was a decrease of IL-32 expression in cells
exposed to S. aureus strains.
Conclusion: Taking into account that endogenous IL-32 controls the production of IL-6, IFN-γ and TNF-α during some infection, the decrease of IL-32 expression in cells exposed to S.
aureus, could be partially responsible for the weak immune response during staphylococcal infection, which may be favorable for the development of chronic mastitis.