Expression of TLR9 in leukocytes from bone marrow, peripheral blood and nasal lavage fluid. Histogram plots of intracellular staining of TLR9 in neutrophils, eosinophils, basophils, monocytes, lymphocytes and immature granulocytes. Expression of TLR9 in leukocytes was analyzed by flow cytometry using mAbs against human TLR9 (open histograms). Cells were fixed and permeabilized prior to incubation with mAbs. Shaded histograms represent cells labeled with isotype-matched control Ab. The data shown were obtained from a control subject and they are representative of those from six independent experiments.