LTB4 production in CGD PMN was dependent on cell density and on the LTB4 receptor BLT1. (A) Mouse BM neutrophils (1 × 10⁶/mL) were stimulated for 1 hour or 5 hours with zymosan (MOI = 2) in RPMI 1640 (0.4 mM Ca²⁺). n = 18 per group (1 hour) and n = 8 per group (5 hours) from more than 3 separate experiments. ^#P < .05; ^##P < .01; ^###P < .001, by paired t test; ***P < .001, by Student t test. (B) Mouse BM neutrophils (4 × 10⁶/mL or 1 × 10⁶/mL) were pretreated with 10 µM U75302 for 10 minutes and then stimulated for 1 hour or 5 hours with zymosan (MOI = 2) in RPMI 1640 (0.4 mM Ca²⁺) in the presence of 10 µM U75302. n = 4 per group from 2 separate experiments. **P < .01, paired t test. (A-B) LTB4 levels in culture supernatant were measured by ELISA. Data are means ± standard error of the mean. (C) SOCE in neutrophils from WT and CGD mice was measured by flow cytometry. Mouse BM neutrophils loaded with 3 µM indo-1 were stimulated with 0.5 ng/mL LTB4 with the indicated amounts of extracellular calcium. (D) Quantification of SOCE (area under the curve [AUC]). Data are means ± standard error of the mean from 2 to 3 independent experiments. *P < .05, by Student t test. MOI, multiplicity of infection.