The effect of dasatinib on recognition of innate immune ligands and antimicrobial activity. Human neutrophils pretreated with the indicated concentrations of dasatinib were stimulated with 10 mg/mL of zymosan (Zym) that was opsonized with normal or heat-inactivated (HI) human serum or left unopsonized (A-B), 1 μg/mL of Pam₃CSK₄ (Pam₃; C-D), or with 1 μg/mL of ultrapurified LPS (upLPS; D), followed by assessment of respiratory burst (A), ERK and p38 MAPK phosphorylation (B,D), or gelatinase release (C). (E-F) Killing of S aureus or E coli (E) and phagocytosis of GFP-expressing S aureus (F) by human neutrophils pretreated with the indicated concentrations of dasatinib. Kinetic curves in panels A and E show mean and SD of representative experiments, and the dose-response curves in these panels show mean and SEM of the percent response from 3-6 independent experiments. Panels B through D show representative results from 3 independent experiments. Panel F shows mean and SEM of mean fluorescence intensity (MFI) values from 3-4 independent experiments after subtraction of samples without bacteria at the 0 time point and expressed as a percentage of the indicated sample. The mean and SEM of phosphorylation of the various MAPKs in the stimulated samples after subtraction of unstimulated control values in the presence of 10nM, 100nM, and 1μM dasatinib was, respectively: 62% ± 27%, 5% ± 2%, and 5% ± 3% (B; unopsonized Zym; p38 MAPK); 81% ± 23%, 43% ± 9%, and 52% ± 26% (B; unopsonized Zym; ERK); 42% ± 19%, 7% ± 7%, and 5% ± 5% (B; HI serum-opsonized Zym; p38 MAPK); 56% ± 24%, 37% ± 16%, and 72% ± 38% (B; HI serum-opsonized Zym; ERK); 73% ± 12%, 9% ± 4%, and 4% ± 4% (B; normal serum-opsonized Zym; p38 MAPK); 84% ± 1%, 69% ± 2%, and 89% ± 11% (B; normal serum-opsonized Zym; ERK); 160% ± 38%, 138% ± 57%, and 55% ± 24% (D; Pam₃); and 154% ± 31%, 72% ± 24%, and 15% ± 14% (D; upLPS) of that in the absence of dasatinib.