Mastitis is an inflammatory disease of the mammary gland, which affects almost half of all dairy cattle and thus leads to huge financial losses in the dairy industry. The disease can lower milk yield and milk quality significantly, as it can affect the amount and destabilize the ratio between milk proteins. Various pathogens can cause mastitis, among which E. coli and S. aureus are the most common. In this work, the effect of lipopolysaccharide (LPS) and lipoteichoic acid (LTA), the key components of pathogens’ cell wall and virulent factors, on immune response and protein synthesis in mammary gland was comparatively investigated. For this purpose, primary bovine mammary epithelial cells were successfully cultured in vitro and stimulated for 24 hours with LPS and LTA, respectively. The qPCR results showed the gene expression of inflammatory factors was increased after overnight stimulation, where LPS led to greater increase than LTA. ELISA demonstrated higher concentrations of IL-8 and TNF-α in LPS-stimulated cultures, whereas LTA decreased them. Established cultures were able to synthesize milk proteins, as it was shown with immunostaining. Differential gene expression analysis showed no changes in gene expression for most milk proteins, only PAEP was downregulated, while CSN1S1 was upregulated. Our findings could lead to better understanding of immune response in mammary gland, especially the early stages of activation of inflammatory response through epithelial cells, and could represent the basis for subsequent studies of mastitis in vitro.
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