ARG1 is synthesized in myelocytes/metamyelozytes and stored in gelatinase granules of mature neutrophils. (Ai) Populations highly enriched in promyelocytes (PMs), myelocytes/metamyelocytes (MYs), bone marrow neutrophils (bm-PMNs), and peripheral blood neutrophils (pb-PMNs) were isolated from bone marrow (BM) and peripheral blood (PB) samples collected from healthy persons. Total mRNA was isolated and subjected to microarray analysis to monitor the mRNA expression profiles for ARG1, myeloperoxidase (MPO; marker for azurophilic granules), lactoferrin (LF; marker for specific granules), and gelatinase (GEL; marker for gelatinase granules) during granulocytic differentiation (mean ± SD, n = 3). (Aii) Western blot analysis of BM and PB populations using antibodies against MPO (proform 89 kDa and heavy chain 64 kDa), LF (78 kDa), GEL (92 kDa), and arginase 1 (ARG1; 35 kDa). Lysates of 3 × 105 cells were loaded in each lane. (Aiii) Subcellular fractions, highly enriched in azurophilic granules (AGs), specific granules (SGs), gelatinase granules (GGs), secretory vesicles (SVs), and cytosol (CYT) were isolated from 108 cells and subjected to Western blot analysis (Aii). (B) Wright Giemsa stained cytospins of BM and PB populations were examined under a BX51 microscope equipped with a DP70 photosystem with analySIS 5.0 software (Olympus, Hamburg, Germany) and a 40×/0.85 numeric aperture oil objective. PowerPoint (Microsoft, Redwood, WA) was used to prepare the images.
