Fig. 4. Expressions of antimicrobial peptide mRNA in bovine mammary epithelial cells (bMECs) stimulated with Mycoplasma bovis, Staphylococcus aureus, or Escherichia coli; bMECs were incubated with M. bovis, S. aureus, or E. coli, live or heat-killed, at multiplicities of infection of 10 (△), 100 (□), and 1,000 (●) for 6, 12, and 24 h. Expressions of lactoferrin (Lf) and β-defensin mRNA were determined by real-time polymerase chain reaction and expressed as fold increases, as described in Materials and Methods section. The data are expressed as mean ± SE values from five independent experiments. Significant differences (^*p<0.05 or ^**p<0.01) compared with unstimulated bMECs.