CARATTERIZZAZIONE IN VITRO DELLA RISPOSTA A STIMOLI INFETTIVI DELLE CELLULE EPITELIALI MAMMARIE BOVINE (BME-UV)

In vitro assessment of bovine mammary epithelial cells response to infectious stimuli Non-specific (innate) immune response plays a major role in defending the udder from bacterial invasion. Moreover, recent investigations suggest that mammary gland epithelial cells could have a large and important role as a source of soluble components of immune defenses. An experimental model was developed based on BME-UV cell line, Staphylococcus aureus as a challenge to assess the interactions among epithelial cells and bacteria by measuring cytokine and three lysosomal enzymes, lysozyme lactoferrin and N-acetyl-b-D-glucosaminidase (NAGase), in S. aureus-stimulated MGEC. S.aureus strains invading epithelial cells elicited an immunological response with levels related to strain characteristics. We found that BME-UV cells didn’t produce lactoferrin. NAGase and Lysozyme have a similar substrate as a target, but our results suggest different secretion mechanisms . These data confirms that epithelial cells could play an important role in udder innate defenses. Besides we investigate the expression of the bovine cathelicidins BMAP-27, BMAP-28, Bac5, and indolicidin in lipopolysaccharide (LPS)-treated cells to examine their potentials to trigger defense responses in bovine mammary cells. Our results indicate multiple roles for the bovine cathelicidins with complementary and mutually enhanced antimicrobial activities. We also investigate the potential effects of tylosin, a macrolide antimicrobial on the immune system. The results of this study confirmed that tylosin could have a significant effect on the release of Lysozyme, NAGase and cytokines by bovine epithelial cells without affecting cell functions. This study showed that an in-vitro model based on S. aureus challenge on epithelial cells could be helpful in assessing both the intracellular and extracellular activity of antimicrobials and their influence on epithelial cell immune and inflammatory response.