Imatinib treatment induces expansion of myeloid cells in mouse spleen and blood.

<p>C57Bl/6 mice were administered imatinib at 66mg/kg/day (Imatinib) or left untreated (Control). For some experiments, mice were either injected in the tail vein with 10⁵ CFU Mm 1218R one day after administration of drug (Mm + imatinib) or carrier (Mm). Neutrophils (CD11b⁺ Ly6C^int Gr-1^hi SSC^int), monocytes (CD11b⁺ Ly6C^hi Gr-1^int SSC^low and F4/80⁺) and eosinophil (CD11b⁺ Ly6C^lo Gr-1^int SSC^hi and F4/80⁺) <b>(A),</b> or T cells (Thy1.2⁺), B cells (B220⁺ CD19⁺) and NK cells (NK1.1⁺) <b>(B)</b> were enumerated by flow cytometry in the blood (top panel) or spleen (bottom panel) at d7 post infection or treatment. Each symbol represents one mouse. Data shown are representative of six independent experiments. <b>(C)</b> Sections of spleens taken from mice left untreated or treated with imatinib at 66mg/kg/day plus or minus infection with Mm. Sections were stained with anti-CD169 to recognize marginal zone macrophages (green), anti-F4/80 to recognize red pulp myeloid cells (blue), and anti-CD11b to recognize neutrophils and monocytes (red). <b>(D)</b> C57Bl/6 mice were administered imatinib at 66 mg/kg/day for 28 days. On day 0, 7, 14, 21, 28 of treatment, mice were bled from the tail vein and numbers of neutrophils and monocytes enumerated by flow cytometry (three mice per time point). Data shown are from two independent experiments. For all data sets, the line in each group of data points represents the median. For <b>A</b>, and <b>B</b>, a Mann-Whitney test was used for pairwise comparisons (e.g. +/- drug or +/- infection only), and a Kruskal Wallis test for multiple comparisons across groups. For all panels, p values less than 0.05 were considered significant; p values < 0.05 are denoted by *, values <.001 by **, and values <.0001 by ***, and values <.00005 by ****.