Riming responses were still observed in monocytedepleted PBMCs, although the level of priming was reduced in two out of three experiments (Figure S2). These results suggested that monocytes likely contributed to the response in the mixed population, but were not required for the response. We then examined the importance of NKp46+ cells, since they are a major source of IFNc induced by IL-12 and IL-18 in bovine GDC-0152 lymphocytes [41]. NKp46, also known as CD335, is a NK cell marker, although it is expressed by other minor leukocytepopulations, including some cd T cells [41]. To test theimportance of these cells, we 1531364 depleted cells expressing CD335 from bovine PBMCs and found that nearly all of the oenothein Binduced IFNc priming response was absent compared to undepleted PBMCs (Figure 4A). Because CD335 is expressed on some cd T cells [41], we examined whether cd T cells contributed to the oenothein Binduced IFNc response. Removal of cd T cells reduced, but did not eliminate, the priming response (Figure S2). This result suggested that, like monocytes, cd T cells contributed to, but were not required for, the response and further suggested that cd TCR2/CD335+ cells were the GW433908G web primary source of IFNc in these assays. As a final approach to confirm these results, multi-color intracellular cytokine analyses were performed. As shown in Figure 4, oenothein B-primed, IL-18-treated CD335+ cells expressed IFNc (Figure 4B and 4C). The percentage of CD335+ cells was also enhanced by oenothein B (Figure 4C). However, this was likely due to activated monocytes adhering to the sample plates and being removed from the CD335- population rather than an expansion of CD335+ cells. Collectively, these data indicate that CD335+ NK cells are the major source of IFNc produced in response to oenothein B and IL-18 in the bovine system.Stimulation of Lymphocytes by Oenothein BFigure 6. Priming of human NK cells to IL-18 by oenothein B. (A) Human PBMCs (105 cells/well) were treated with the indicated concentrations of oenothein B or X-VIVO medium alone for 48 hrs, and expression of IL-18R on human NK cells was determined by flow cytometry. Significance was determined by One-way ANOVA with Bonferroni post-test. *p,0.05, **p,0.01 (B) Human PBMCs (105 cells/well) were treated with 20 mg/ml oenothein B or X-VIVO medium alone for 48 hrs. Cells were washed with PBS and treated with 50 ng/ml rhu IL-18 for 6 hrs in the presence of brefeldin A. IFNc staining [mean fluorescent intensity (MFI)] on human NK cells was determined by flow cytometry. The graphs represent data from five individuals, with each treatment analyzed in triplicate. (C) Representative examples of two-color flow cytometry plots comparing IFNc staining on gated human NK cells treated with 20 mg/ml oenothein B, 50 24786787 ng/ml rhuIL-18, both, or X-VIVO medium alone. *p,0.05, **p,0.01, ***p,0.001. doi:10.1371/journal.pone.0050546.gOenothein B Induces IFNc Production by Human Innate LymphocytesIn our previous studies with oenothein B, we showed that treatment of human PBMCs with oenothein B promoted some IFNc production, in contrast to the response we observed with bovine cells [7]. However, potential sources of this cytokine were not identified. We first confirmed our previous results in human PBMCs by cytokine ELISA (Figure 5A). We then examined if lymphocytes were a source of this induced IFNc. Human T cells, including cd T cells and CD8+ T cells, produced IFNc in response to oenothein B (Figure 5B and 5C). The percentage.Riming responses were still observed in monocytedepleted PBMCs, although the level of priming was reduced in two out of three experiments (Figure S2). These results suggested that monocytes likely contributed to the response in the mixed population, but were not required for the response. We then examined the importance of NKp46+ cells, since they are a major source of IFNc induced by IL-12 and IL-18 in bovine lymphocytes [41]. NKp46, also known as CD335, is a NK cell marker, although it is expressed by other minor leukocytepopulations, including some cd T cells [41]. To test theimportance of these cells, we 1531364 depleted cells expressing CD335 from bovine PBMCs and found that nearly all of the oenothein Binduced IFNc priming response was absent compared to undepleted PBMCs (Figure 4A). Because CD335 is expressed on some cd T cells [41], we examined whether cd T cells contributed to the oenothein Binduced IFNc response. Removal of cd T cells reduced, but did not eliminate, the priming response (Figure S2). This result suggested that, like monocytes, cd T cells contributed to, but were not required for, the response and further suggested that cd TCR2/CD335+ cells were the primary source of IFNc in these assays. As a final approach to confirm these results, multi-color intracellular cytokine analyses were performed. As shown in Figure 4, oenothein B-primed, IL-18-treated CD335+ cells expressed IFNc (Figure 4B and 4C). The percentage of CD335+ cells was also enhanced by oenothein B (Figure 4C). However, this was likely due to activated monocytes adhering to the sample plates and being removed from the CD335- population rather than an expansion of CD335+ cells. Collectively, these data indicate that CD335+ NK cells are the major source of IFNc produced in response to oenothein B and IL-18 in the bovine system.Stimulation of Lymphocytes by Oenothein BFigure 6. Priming of human NK cells to IL-18 by oenothein B. (A) Human PBMCs (105 cells/well) were treated with the indicated concentrations of oenothein B or X-VIVO medium alone for 48 hrs, and expression of IL-18R on human NK cells was determined by flow cytometry. Significance was determined by One-way ANOVA with Bonferroni post-test. *p,0.05, **p,0.01 (B) Human PBMCs (105 cells/well) were treated with 20 mg/ml oenothein B or X-VIVO medium alone for 48 hrs. Cells were washed with PBS and treated with 50 ng/ml rhu IL-18 for 6 hrs in the presence of brefeldin A. IFNc staining [mean fluorescent intensity (MFI)] on human NK cells was determined by flow cytometry. The graphs represent data from five individuals, with each treatment analyzed in triplicate. (C) Representative examples of two-color flow cytometry plots comparing IFNc staining on gated human NK cells treated with 20 mg/ml oenothein B, 50 24786787 ng/ml rhuIL-18, both, or X-VIVO medium alone. *p,0.05, **p,0.01, ***p,0.001. doi:10.1371/journal.pone.0050546.gOenothein B Induces IFNc Production by Human Innate LymphocytesIn our previous studies with oenothein B, we showed that treatment of human PBMCs with oenothein B promoted some IFNc production, in contrast to the response we observed with bovine cells [7]. However, potential sources of this cytokine were not identified. We first confirmed our previous results in human PBMCs by cytokine ELISA (Figure 5A). We then examined if lymphocytes were a source of this induced IFNc. Human T cells, including cd T cells and CD8+ T cells, produced IFNc in response to oenothein B (Figure 5B and 5C). The percentage.
