Staphylococcus aureus and Escherichia coli Cause Deviating Expression Profiles of Cytokines and Lactoferrin Messenger Ribonucleic Acid in Mammary Epithelial Cells

Bovine mammary gland epithelial cells in cell culture environment. On the first day isolated acini are already attached on the tissue flask surface (a). New epithelial cells are growing out of the acinus on the second day (b). Typical cobblestone-like conformation of epithelial cells on the fifth day of cultivation (c).

Pathogen recognition: mRNA expression (ΔΔCT) of Toll-like receptor 2 and Toll-like receptor 4 of 28 cows after treatment with Escherichia coli and Staphylococcus aureus for 1, 6, and 24h (t). Data are presented as means ± SEM. ^a–cMeans without common letters within the S. aureus-treated group differ significantly at the measured time points (P<0.05). ^A–CMeans without common letters within the E. coli-treated group differ significantly at the measured time points (P<0.05). Significant differences between E. coli- and S. aureus-treated cells within one time point are indicated by ** (P<0.01).

Signal transmission: mRNA expression (ΔΔCT) of RelA, a subunit of nuclear factor-κB, of 28 cows after treatment with Escherichia coli and Staphylococcus aureus for 1, 6, and 24h (t). Data are presented as means±SEM. ^a,bMeans without common letters within the S. aureus-treated group differ significantly at the measured time points (P<0.05). ^A,BMeans without common letters within the E. coli-treated group differ significantly at the measured time points (P<0.05). Significant differences between E. coli- and S. aureus-treated cells within one time point are indicated by * (P<0.05) and *** (P<0.001).

Signaling pattern: mRNA expression (ΔΔCT) of tumor necrosis factor alpha, IL-1 beta, IL-6, IL-8, and RANTES of 28 cows after treatment with Escherichia coli and Staphylococcus aureus for 1, 6, and 24h (t). Data are presented as means±SEM; a trendline is shown to emphasize the deviating expression profile between E. coli and S. aureus. ^a–cMeans without common letters within the S. aureus-treated group differ significantly at the measured time points (P<0.05). ^A–CMeans without common letters within the E. coli-treated group differ significantly at the measured time points (P<0.05). Significant differences between E. coli- and S. aureus-treated cells within one time point are indicated by * (P<0.05), ** (P<0.01), and *** (P<0.001).

Lactoferrin: mRNA expression (ΔΔCT) of lactoferrin of 28 cows after treatment with Escherichia coli and Staphylococcus aureus for 1, 6, and 24h (t). Data are presented as means±SEM; a trendline is shown to emphasize the deviating expression profile between E. coli and S. aureus. ^a,bMeans without common letters within the S. aureus-treated group differ significantly at the measured time points (P<0.05). ^A,BMeans without common letters within the E. coli-treated group differ significantly at the measured time points (P<0.05). Significant differences between E. coli- and S. aureus-treated cells within one time point are indicated by * (P<0.05) and ** (P<0.01).

Complement system: mRNA expression (ΔΔCT) of complement factor 3 of 28 cows after treatment with Escherichia coli and Staphylococcus aureus for 1, 6, and 24h (t). Data are presented as means±SEM. ^a-cMeans without common letters within the S. aureus-treated group differ significantly at the measured time points (P<0.05). ^A,BMeans without common letters within the E. coli-treated group differ significantly at the measured time points (P<0.05).