Effects of PI3K inhibitors on PtdIns(3,4,5)P₃ accumulation in fMLP-stimulated, TNF-α-primed mouse neutrophils. Bone marrow neutrophils derived from the indicated strains of mice were labeled with [³²P]Pi in the presence of 500 U/mL TNF-α, as described in “Materials and methods.” Neutrophils were washed, warmed to 37°C over 5 minutes in the presence of the indicated concentration of inhibitor, and stimulated with 10 μM fMLP or vehicle for the indicated times. Incubations were terminated, and [³²P]-phosphoinositides were quantified as described in “Materials and methods.” Data shown are for the levels of [³²P] PtdIns(3,4,5)P₃ (mean ± SD or range, n = 2-3, collected from separate preparations of neutrophils).