Ent structural and immunological properties than OPCs [7]. Therefore, we investigated whether CP21 manufacturer oenothein B might induce IFNc production in innate lymphocytes or, based on our earlier studies that showed OPCs can enhance responses to secondary signals, possibly prime innate lymphocytes to respond more robustly to known inducers of IFNc, such as IL-18 [25]. Briefly, oenothein B is a dimeric, macrocyclic ellagitannin isolated from Epilobium angustifolium, as well as other plant sources. It has been studied for antitumor, antiviral, antibacterial, antioxidant, pro-inflammatory, and anti-inflammatory properties [7], [26?1]. Oenothein B has been reported to inhibit inflammatory responses by phagocytes induced by TLR agonists and other stimulants [30], [31]. However, in the absence of additional stimulation, oenothein B promotes inflammatory responses by phagocytes. In studies conducted in the early 1990’s, oenothein BStimulation of Lymphocytes by Oenothein Bwas shown to reduce the growth of several tumors in vivo and activate macrophages, promoting the production of IL-1 [28]. Induced IL-1 production was proposed to be important in the antitumor properties of oenothein 
B, although this has not been directly tested. We recently showed that oenothein B induces the production of IL-1, as well as other pro-inflammatory cytokines, including IL-6 and tumor necrosis factor a (TNFa), by monocytes [7], responses not seen with OPCs. In addition, we showed that substructures of oenothein B did not stimulate phagocytes to the same extent as oenothein B [7], suggesting an important role for the complete structure in its immunological activity. To date, there are no reports on the effects of oenothein B on lymphocytes. We now show that oenothein B stimulates innate lymphocytes (cd T cells and NK cells) and promotes their production of IFNc. We also describe a novel priming effect of oenothein B on NK cells, leading to enhanced IFNc production following IL-18 treatment. Finally, we describe a similar priming effect of oenothein B in response to a tumor cell line.Materials and Methods Ethics StatementAll animal experiments were performed in accordance with National Institutes of Health guidelines and approved by the Institutional Animal Care and Use Committee of Montana State University (protocol identification: 2009?, 2011?1). Human subjects testing was performed in accordance with a protocol approved by the Institutional Review Board of Montana State University (approval identification: MJ032609), and written, informed consent was obtained from all individuals. No specific permits were required for the described field studies involving 24786787 E. angustifolium. According to the Gallatin National Forest Office (Montana), collection of limited amounts of plant materials for non-commercial, educational purposes does not require a permit. All plants were collected from a National Forest and public land and no endangered or protected species were collected.Figure 1. Oenothein B induces IL-2Ra or CD69 on bovine and human lymphocyte subsets. (A) Bovine PBMCs (105 cells/well) were treated with the indicated concentrations of oenothein B in X-VIVO medium for 24 hrs, and IL-2Ra expression on cd T cells and NK cells was Pluripotin site measured by multi-color flow cytometry. NK cells were defined as non-cd T cells that expressed CD335. The graphs represent pooled data from 3 individuals. Each treatment was analyzed in triplicate and error bars indicate SEM. Significance compared to untreated.Ent structural and immunological properties than OPCs [7]. Therefore, we investigated whether oenothein B might induce IFNc production in innate lymphocytes or, based on our earlier studies that showed OPCs can enhance responses to secondary signals, possibly prime innate lymphocytes to respond more robustly to known inducers of IFNc, such as IL-18 [25]. Briefly, oenothein B is a dimeric, macrocyclic ellagitannin isolated from Epilobium angustifolium, as well as other plant sources. It has been studied for antitumor, antiviral, antibacterial, antioxidant, pro-inflammatory, and anti-inflammatory properties [7], [26?1]. Oenothein B has been reported to inhibit inflammatory responses by phagocytes induced by TLR agonists and other stimulants [30], [31]. However, in the absence of additional stimulation, oenothein B promotes inflammatory responses by phagocytes. In studies conducted in the early 1990’s, oenothein BStimulation of Lymphocytes by Oenothein Bwas shown to reduce the growth of several tumors in vivo and activate macrophages, promoting the production of IL-1 [28]. Induced IL-1 production was proposed to be important in the antitumor properties of oenothein B, although this has not been directly tested. We recently showed that oenothein B induces the production of IL-1, as well as other pro-inflammatory cytokines, including IL-6 and tumor necrosis factor a (TNFa), by monocytes [7], responses not seen with OPCs. In addition, we showed that substructures of oenothein B did not stimulate phagocytes to the same extent as oenothein B [7], suggesting an important role for the complete structure in its immunological activity. To date, there are no reports on the effects of oenothein B on lymphocytes. We now show that oenothein B stimulates innate lymphocytes (cd T cells and NK cells) and promotes their production of IFNc. We also describe a novel priming effect of oenothein B on 
NK cells, leading to enhanced IFNc production following IL-18 treatment. Finally, we describe a similar priming effect of oenothein B in response to a tumor cell line.Materials and Methods Ethics StatementAll animal experiments were performed in accordance with National Institutes of Health guidelines and approved by the Institutional Animal Care and Use Committee of Montana State University (protocol identification: 2009?, 2011?1). Human subjects testing was performed in accordance with a protocol approved by the Institutional Review Board of Montana State University (approval identification: MJ032609), and written, informed consent was obtained from all individuals. No specific permits were required for the described field studies involving 24786787 E. angustifolium. According to the Gallatin National Forest Office (Montana), collection of limited amounts of plant materials for non-commercial, educational purposes does not require a permit. All plants were collected from a National Forest and public land and no endangered or protected species were collected.Figure 1. Oenothein B induces IL-2Ra or CD69 on bovine and human lymphocyte subsets. (A) Bovine PBMCs (105 cells/well) were treated with the indicated concentrations of oenothein B in X-VIVO medium for 24 hrs, and IL-2Ra expression on cd T cells and NK cells was measured by multi-color flow cytometry. NK cells were defined as non-cd T cells that expressed CD335. The graphs represent pooled data from 3 individuals. Each treatment was analyzed in triplicate and error bars indicate SEM. Significance compared to untreated.