Tyrosine phosphorylation in neutrophils from healthy individuals and patients with severe sepsis. (A) Increased tyrosine phosphorylation in neutrophils from patients with sepsis. Freshly isolated neutrophils (1 × 106/mL) from healthy humans (control) and patients with severe sepsis (patient) were cultured with or without the protein-tyrosine phosphatase inhibitor phenylarsine oxide (PAO; 10 μmol/L) for 30 minutes at 37°C. (B) Inhibition of tyrosine phosphorylation in normal neutrophils by IL-10. Freshly isolated neutrophils (1 × 106/mL) from healthy humans were cultured with or without LPS (1 μg/mL) and rhIL-10 (100 U/mL) for 2 hours at 37°C. Levels of tyrosine phosphorylation were analyzed by flow cytometry after permeabilization with saponin and staining with antiphosphotyrosine (P-Tyr) and goat-antimouse FITC-conjugated antibodies. Both figures are representative of three other experiments that yielded the same results.
