Figure 2.
Identification of arginase expressing cells. (a) Identification of arginase I-expressing cells. The region containing cells expressing arginase I (A) was identified by back-gating ungated arginase I-positive cells (U) on the side scatter/forward scatter plot. (b) Frequency of arginase I-expressing cells. In region A, two populations of CD14+ cells were identified: CD14low (C) and CD14high (D)(CD14–: B, dotted line: unstained cells). The frequency of arginase-expressing cells was determined in region B (CD14–), C (CD14low) and D (CD14high). The markers of histograms and dot-plot were set according to the fluorescence of unstained cells and the value in parenthesis represents the percentage of cells positive for the isotype control. Data show the results of one representative experiment out of four independent experiments. (c) Neutrophils and alternatively activated macrophages express arginase I. Arginase I was expressed in 77.8% of CD15+CD14– cells (upper left), 90.8% of CD15+CD14low cells (upper right) and 25.3% of CD14lowCD206+ cells (lower left); the isotype control for arginase I in CD14lowCD206+ is shown in the lower right (1.7%). Data show the results of one representative experiment out of four independent experiments. (d) Arginase activity in peripheral neutrophils is increased during pregnancy. Neutrophils were isolated by double-density gradient centrifugation of Histopaque®-1119 and 1077 and arginase activity was measured as described in Material and methods. Each symbol represents arginase activity of the cells from one individual and the horizontal bar represents the median. Statistical differences were determined using the Mann-Whitney test: *p=0.02.