Effects of Imatinib on CXCR2 expression, activation, and apoptosis in neutrophils.

<p>C57Bl/6 mice were administered imatinib at 66 mg/kg/d or left untreated. Beginning 24h post-treatment mice were either injected in the tail vein with 10⁵ CFU Mm 1218R or left uninfected. At 7d post-treatment, bone marrow was collected from both femurs. <b>(A</b>) Representative flow cytometry plots of CXCR4 and CXCR2 expression on neutrophils from bone marrow using flow cytometry. CXCR2^hiCXCR4^lo and CXCR4^hiCXCR2^lo subsets were identified, and frequencies of total neutrophils are displayed in boxes. <b>(B)</b> Median fluorescence intensity (MFI) of CXCR2 and CXCR4 on neutrophils from bone marrow. Cumulative data from two independent experiments are presented with six mice per condition. The line in each data set represents the median. <b>(C)</b> C57Bl/6 mice were treated as in <b>A</b>. Activation status was assessed by surface expression of CD66b (secondary granules), CD63 (primary granules) and apoptosis by intracellular staining for caspase 3 and 7 activity of the total neutrophils (Ly6G⁺Ly6C⁺) from spleen. Cumulative data from two independent experiments are presented with 6 mice per condition. <b>(D</b>) C57Bl/6 mice were administered imatinib at 66mg/kg/d or left untreated. On d7, splenic neutrophils were isolated using Ly6G⁺ microbeads and 4 x10⁶ cells were injected via the left tail vein into each naïve recipient mice, and infected via the right tail vein with 10⁵ CFU Mm. Forty eight hours later, spleens were harvested and CFU/gram were determined. CFU/g spleen from mice injected with carrier, or with neutrophils from imatinib-treated mice or mice treated with carrier (water). Cumulative data from three independent experiments are presented with 15–25 animals per condition. The line represents the median. A Mann-Whitney test was used for pairwise comparisons, and a Kruskal Wallis test for multiple comparisons.