Impaired degranulation in syk^−/− neutrophils in response to bacteria. (A) Flow cytometric analysis of CD11b and CD62L levels on WT or syk^−/− neutrophils stimulated for 60 minutes with rag1^−/− serum-opsonized (op) S aureus (MOI = 5) or E coli (MOI = 10). Neutrophils of the indicated genotype were quantified for CD11b (MFI) after stimulation with (B) S aureus or (C) E coli; percentage CD62L⁻ (shed) after stimulation with (D,F) S aureus, (E,G) E coli, or (H-I) bacteria opsonized with heat-inactivated (HI op) serum. (J) Release of gelatinase granules by WT or syk^−/− neutrophils stimulated in suspension with S aureus or E coli for 60 minutes and analyzed by gelatinase zymogram. (K) Quantitation of gelatinase zymogram (MOI = 1). (L) Lactoferrin release (MOI = 1). Error bars represent SD. *P < .05, **P < .01, ^#P < .001 compared with WT by 2-way analysis of variance (ANOVA) with Bonferroni posttests. All data are representative of 3 or more independent experiments.