Figure 7.

Antimicrobial and Mx1-inducing activity of neutrophil-derived supernatants. (A,B) Antimicrobial activity against both Gram-negative and Gram-positive bacteria was observed with supernatants of phorbol myristate acetate-treated neutrophils. Supernatants were mixed with approximately 5 × 10³ CFU of Escherichia coli 9217/10 (A) and Staphylococcus aureus M3842 (B), and incubated at 37°C for 1 h. As control, bacteria were incubated in FBS-free medium. Each sample was then diluted 10-fold in PBS, and 50 µl of suspensions were plated on petri dishes to determine the CFU/ml. Each symbol represents at least a triplicate from one animal, and the line shows the average of all animals. Significant differences compared to the medium alone were calculated using Dunnett’s multiple comparison test (*p < 0.05). (C) Enhancement of nucleic acid sensing in bovine turbinate epithelial cells (BT cells) by neutrophil supernatants. Supernatants were incubated with or without 0.1 µg/ml poly(I:C) for 10 min before being transferred to BT cells. After 20 h, Mx1 and β-actin expression were determined by western blot. One representative experiment out of four is shown.