Identification of Potential Immunogenic Molecules During the Allogeneic Transplantation of Human Adipose-derived Mesenchymal Stem Cells

2020 ◽  
Author(s):  
Dongdong Wang ◽  
Yi Fu ◽  
Junfen Fan ◽  
Chao Li ◽  
Yi Xu ◽  
...  
Keyword(s):  
Stem Cells ◽  
T Cells ◽  
Mesenchymal Stem Cells ◽  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Allogeneic Transplantation ◽  
Peripheral Blood Mononuclear ◽  
Nsg Mice

Abstract Background: Given their low immunogenicity and multiple differentiation capacities, mesenchymal stem cells (MSCs) have the potential to be used for “off-the-shelf” cell therapy. However, MSC allorejection indicates that they are not fully immune privileged. In this study, we investigated the immunogenicity of human adipose-derived MSCs (Ad-MSCs) and identified potential immunogenic molecules.Methods: To evaluate the immunogenicity of human Ad-MSCs in vivo, cells were transplanted into humanized mice (hu-mice), and T cell infiltration and clearance of human Ad-MSCs were observed by immunofluorescence and bioluminescence imaging. One-way mixed lymphocyte reaction (MLR) and flow cytometry were performed to evaluate the immunogenicity of human Ad-MSCs in vitro. High-throughput TCR repertoire sequencing and mass spectrometry were applied to identify potential immunogenic molecules.Results: Allogeneic human Ad-MSCs recruited T cells during transplantation and caused faster clearance in hu-mice than NOD/ShiLtJGpt-Prkdcem26Cd52Il2rgem26Cd22/Gpt (NSG) mice. The proliferation and activation of T cells was significantly enhanced by human Ad-MSCs, and the expression level of HLA-II on human Ad-MSCs was dramatically increased after coculture with human peripheral blood mononuclear cells (PBMCs) in vitro. In addition, upregulated expression of alpha-enolase (ENO1) on the surface of human Ad-MSCs increased their immunogenicity, and ENO1 inhibitor treatment decreased the human Ad-MSC triggered proliferation of T cells in vitro.Conclusions: We further confirmed the immunogenicity of human Ad-MSCs during allogeneic transplantation and provided a potential target, ENO1, for the safe clinical application of allogeneic human Ad-MSC therapy.

High levels of thyroid hormone impair regulatory T cells function via reduced PD-1 expression

2021 ◽  
Author(s):  
Yi Zhong ◽  
Ting-Ting Lu ◽  
Xiao-Mei Liu ◽  
Bing-Li Liu ◽  
Yun Hu ◽  
...  
Keyword(s):  
T Cells ◽  
Thyroid Hormone ◽  
Regulatory T Cells ◽  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Dependent Manner ◽  
Peripheral Blood Mononuclear

Abstract Context Regulatory T cells (Tregs) dysfunction plays an important role in the development and progression of Graves’ disease (GD). Programmed cell death 1 (PD-1) prompts FoxP3 in Tregs expression and enhances the suppressive activity of Tregs. Whether abnormal expression of PD-1 contributes to the breakdown of Tregs and the role of thyroid hormone in the PD-1 expression of Tregs in GD remain substantially undefined. Objective To evaluate the role of PD-1 in Tregs function and triiodothyronine (T3) in PD-1 expression in patients with GD and mice treated with T3. Methods We recruited 30 patients with GD and 30 healthy donors. PD-1 expression in Tregs and Tregs function were determined. To evaluate the effects of thyroid hormone on PD-1 expression in Tregs, we used T3 for the treatment of human peripheral blood mononuclear cells (PBMCs). We then treated mice with T3 to confirm the effect of thyroid hormone on PD-1 expression in Tregs and Tregs function in vivo. Results PD-1 expression in Tregs and the suppressive function of Tregs significantly decreased in patients with GD. T3 reduced PD-1 expression in human Tregs in a concentration- and time-dependent manner in vitro. High levels of circulating T3 reduced PD-1 expression in Tregs, impaired Tregs function, and disrupted T-helper cell (Th1 and Th2) balance in mice treated with T3. Conclusions Tregs dysfunction in GD patients might be due to down-regulation of PD-1 expression in Tregs induced by high levels of serum T3.

Decitabine Can Increase the Induction of Regulatory γδ T Cells with Enhanced Immunosuppression on Graft-Versus-Host Disease From Adult Human Peripheral Blood Mononuclear Cells

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1901-1901 ◽  
Author(s):  
Yongxian Hu ◽  
Yanjun Gu ◽  
Lixia Sheng ◽  
Huarui Fu ◽  
Kangni Wu ◽  
...  
Keyword(s):  
T Cells ◽  
Survival Time ◽  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Γδ T Cells ◽  
Foxp3 Expression ◽  
Peripheral Blood Mononuclear ◽  
Tgf Β1

Abstract Abstract 1901 Regulatory γδ T cells (γδ Tregs) is a novel subset of cells with immunosuppressive function while methods for γδ Treg induction is rarely introduced and its role in graft-versus-host disease (GVHD) prevention remains unkown. Decitabine, a kind of hypomethylating agents, can act synergistically with TGF-β1 to convert a variety of αβ T cells to regulatory αβ T cells with suppressive function but its role in induction and function of γδ Tregs has not been reported. We show here the role of decitabine for the induction of γδ Tregs. Moreover, we provide functional analysis and underlying mechanisms of decitabine-induced γδ Tregs relative to γδ Tregs without decitabine induction as well as in vivo evidences of their preventions on GVHD. Human peripheral blood mononuclear cells (PBMCs) were cultured with IL-2, IL-15, TGF-β1 and zoledronic acid (ZOL). On day 2, 0.5μmol/ml decitabine was added to aliquots of PBMCs. On days 4, 7, and 10, half of the supernatant volume was replaced with media containing cytokines. On day 11, frequencies of γδ Tregs were detected by flow cytometry (FACS). We found the frequency of γδ Tregs was 36.2% in TGF-β1/IL-15/ZOL stimulated group (referred to as common γδ Tregs below) and 59.9% in IL-2/TGF-β1/IL-15/ZOL/decitabine stimulated group (referred to as decitabine-induced γδ Tregs) (p<0.05). In order to compare immunosuppressive function of the two populations, γδ T cells containing γδ Tregs were isolated by magnetic cell sorting system (MACS) and tested for their ability to suppress proliferation of alloreactive PBMCs using CFSE-based assay. After 5 days of in vitro culture, CFSE-labeled PBMCs proliferation was significantly reduced in the presence of enriched γδ Tregs even at 8:1(PBMCs: γδ Tregs) ratio. The inhibition rate was significantly different (decitabine-induced γδ Tregs VS common γδ Tregs at ratio 1:1 is 81.3% VS 68.2%, p<0.05). To clarify the underlying mechanisms we performed ELISA to measure levels of inhibitory cytokines IL-10, IL-4 and TGF-β1 in supernatant of CFSE-based assay. We noted an elevated IL-10 secretion in the decitabine-induced γδ Tregs group compared with common γδ Tregs group (92.7±11pg/ml VS 10.3±2pg/ml at ratio 1:1, p<0.01). We confirmed the result by intracellular IL-10 detection using FACS. Previous reports showed high levels of inducible T-cell costimulator (ICOS) were correlated with IL-10 synthesis. So γδ Tregs were monitored for ICOS expression by FACS. The result revealed that ICOS expression was up-regulated in decitabine-induced γδ Tregs in contrast to common γδ Tregs (MFI: 268 VS 54). Stability of Foxp3 is a critical factor in the immunosuppressive ability of Tregs. Thus we evaluated the frequency of γδ Tregs after 5 days in CFSE-based assay. We observed loss of Foxp3 expression in decitabine-induced γδ Tregs was negligible (<3%) while 15.5% common γδ Tregs lost foxp3 expression. To confirm the results in vitro we tested the functional ability to prevent GVHD in vivo. GVHD was induced in NOD/SCID mice following busulfan and anti-CD122 condition and 1×107 PBMCs transfusion. Animals were co-injected with either decitabine-induced γδ Tregs or common γδ Tregs at a ratio of 1:1. Survival time and GVHD manifestations of the transplanted mice were evaluated. As a result, transplantation of human PBMCs alone induced lethal GVHD with average survival time 25± 8 days while the survival time was 43± 5 days and 58±7 days in mice co-injected with common γδ Tregs and decitabine-induced γδ Tregs, respectively (p<0.05). Clinical manifestations such as hunched back, diarrhea, and body weight loss were statistically different among 3 groups. To investigate the infiltration of human lymphocytes into nonlymphoid tissues in GVHD mice, we performed immunohistochemical analysis of the liver and intestines using anti-human CD45. Remarkably abundant invasion of human CD45+ cells was observed around the veins in the liver and intestines transplanted with PBMCs alone while less invasion in mice co-injected with common γδ Tregs and the lest invasion in mice co-injected with decitabine-induced γδ Tregs. Altogether, our findings reveal that decitabine and the cytokines can efficiently syngenerize to induce γδ Tregs with enhanced immunosuppression on GVHD which are via higher levels of IL-10 production due to ICOS up-regulation as well as stability of Foxp3 expression. Thus γδ Tregs may be potentially exploited therapeutically in a variety of transplantation settings. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Monocyte tissue factor induction by lipopolysaccharide (LPS): dependence on LPS-binding protein and CD14, and inhibition by a recombinant fragment of bactericidal/permeability-increasing protein

Blood ◽  
1994 ◽  
Vol 83 (9) ◽  
pp. 2516-2525 ◽  
Author(s):  
K Meszaros ◽  
S Aberle ◽  
R Dedrick ◽  
R Machovich ◽  
A Horwitz ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Binding Protein ◽  
Mononuclear Phagocytes ◽  
Factor Vii ◽  
Peripheral Blood Mononuclear ◽  
Recombinant Fragment

Abstract Mononuclear phagocytes, stimulated by bacterial lipopolysaccharide (LPS), have been implicated in the activation of coagulation in sepsis and endotoxemia. In monocytes LPS induces the synthesis of tissue factor (TF) which, assembled with factor VII, initiates the blood coagulation cascades. In this study we investigated the mechanism of LPS recognition by monocytes, and the consequent expression of TF mRNA and TF activity. We also studied the inhibition of these effects of LPS by rBPI23, a 23-kD recombinant fragment of bactericidal/permeability increasing protein, which has been shown to antagonize LPS in vitro and in vivo. Human peripheral blood mononuclear cells, or monocytes isolated by adherence, were stimulated with Escherichia coli O113 LPS at physiologically relevant concentrations (&gt; or = 10 pg/mL). The effect of LPS was dependent on the presence of the serum protein LBP (lipopolysaccharide-binding protein), as shown by the potentiating effect of human recombinant LBP or serum. Furthermore, recognition of low amounts of LPS by monocytes was also dependent on CD14 receptors, because monoclonal antibodies against CD14 greatly reduced the LPS sensitivity of monocytes in the presence of serum or rLBP. Induction of TF activity and mRNA expression by LPS were inhibited by rBPI23. The expression of tumor necrosis factor showed qualitatively similar changes. Considering the involvement of LPS-induced TF in the potentially lethal intravascular coagulation in sepsis, inhibition of TF induction by rBPI23 may be of therapeutic benefit.

scholarly journals Precision engineering of an anti-HLA-A2 chimeric antigen receptor in regulatory T cells for transplant immune tolerance

2021 ◽  
Author(s):  
Yannick D. Muller ◽  
Leonardo M.R. Ferreira ◽  
Emilie Ronin ◽  
Patrick Ho ◽  
Vinh Nguyen ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Chimeric Antigen Receptor ◽  
Mononuclear Cells ◽  
Antigen Receptor ◽  
Single Chain ◽  
Transplant Tolerance ◽  
Peripheral Blood Mononuclear

Infusion of regulatory T cells (Tregs) engineered with a chimeric antigen receptor (CAR) targeting donor-derived human leukocyte antigen (HLA) is a promising strategy to promote transplant tolerance. Here, we describe an anti-HLA-A2 CAR (A2-CAR) generated by grafting the complementarity-determining regions (CDRs) of a human monoclonal anti-HLA-A2 antibody into the framework regions of the Herceptin 4D5 single-chain variable fragment and fusing it with a CD28-zeta signaling domain. The CDR-grafted A2-CAR maintained the specificity of the original antibody. We then generated HLA-A2 mono-specific human CAR Tregs either by deleting the endogenous T-cell receptor (TCR) via CRISPR/Cas9 and introducing the A2-CAR using lentiviral transduction or by directly integrating the CAR construct into the TCR alpha constant locus using homology-directed repair. These A2-CAR+TCRdeficient human Tregs maintained both Treg phenotype and function in vitro. Moreover, they selectively accumulated in HLA-A2-expressing islets transplanted from either HLA-A2 transgenic mice or deceased human donors. A2-CAR+TCRdeficient Tregs did not impair the function of these HLA-A2+ islets, whereas similarly engineered A2-CAR+TCRdeficientCD4+ conventional T cells rejected the islets in less than 2 weeks. A2-CAR+TCRdeficient Tregs delayed graft-versus-host disease only in the presence of HLA-A2, expressed either by co-transferred peripheral blood mononuclear cells or by the recipient mice. Altogether, we demonstrate that genome-engineered mono-antigen-specific A2-CAR Tregs localize to HLA-A2-expressing grafts and exhibit antigen-dependent in vivo suppression, independent of TCR expression. These approaches may be applied towards developing precision Treg cell therapies for transplant tolerance.

scholarly journals The Comparison of the Immunologic Properties of Stem Cells Isolated from Human Exfoliated Deciduous Teeth, Dental Pulp, and Dental Follicles

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Selin Yildirim ◽  
Noushin Zibandeh ◽  
Deniz Genc ◽  
Elif Merve Ozcan ◽  
Kamil Goker ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Dental Pulp ◽  
Fas Ligand ◽  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Venous Blood ◽  
Deciduous Teeth ◽  
Peripheral Blood Mononuclear ◽  
Human Exfoliated Deciduous Teeth

Aim. To compare the effects of various mesenchymal stem cells, those isolated from human exfoliated deciduous teeth (SHEDs), dental pulp stem cells (DPSCs), and dental follicle stem cells (DFSCs), on human peripheral blood mononuclear cells (PBMCs).Method. Mesenchymal stem cells were isolated from three sources in the orofacial region. Characterization and PCR analyses were performed. Lymphocytes were isolated from healthy peripheral venous blood. Lymphocytes were cocultured with stem cells in the presence and absence of IFN-γand stimulated with anti-CD2, anti-CD3, and anti-CD28 for 3 days. Then, lymphocyte proliferation, the number of CD4+FoxP3+T regulatory cells, and the levels of Fas/Fas ligand, IL-4, IL-10, and IFN-γin the culture supernatant were measured.Results. The DFSCs exhibited an enhanced differentiation capacity and an increased number of CD4+FoxP3+T lymphocytes and suppressed the proliferation and apoptosis of PBMCs compared with SHEDs and DPSCs. The addition of IFN-γaugmented the proliferation of DFSCs. Furthermore, the DFSCs suppressed IL-4 and IFN-γcytokine levels and enhanced IL-10 levels compared with the other cell sources.Conclusion. These results suggest that IFN-γstimulates DFSCs by inducing an immunomodulatory effect on the PBMCs of healthy donors while suppressing apoptosis and proliferation and increasing the number of CD4+FoxP3+cells.

Simvastatin Suppresses Interleukin Iβ Release in Human Peripheral Blood Mononuclear Cells Stimulated With Cholesterol Crystals

2018 ◽  
Vol 23 (6) ◽  
pp. 509-517 ◽  
Author(s):  
Anna J. Boland ◽  
Nisha Gangadharan ◽  
Pierce Kavanagh ◽  
Linda Hemeryck ◽  
Jennifer Kieran ◽  
...  
Keyword(s):  
Cardiovascular Disease ◽  
Peripheral Blood Mononuclear Cells ◽  
Nlrp3 Inflammasome ◽  
Peripheral Blood ◽  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Peripheral Blood Mononuclear ◽  
Blood Mononuclear Cells

Statins are mainstream therapy in the treatment and prevention of cardiovascular disease through inhibitory effects on cholesterol synthesis. However, statins’ beneficial effects in cardiovascular disease may also be attributable to their role as anti-inflammatory mediators. Here, we investigated the effects of simvastatin treatment on expression levels of interleukin (IL) 1β in both patient with hyperlipidemia and healthy human peripheral blood mononuclear cells (PBMCs) using cholesterol crystals (CC), a cardiovascular pathogenic stimulus for activation of the NOD-like receptor pyrin domain–containing protein 3 (NLRP3) inflammasome. Cholesterol crystal-induced NLRP3 inflammasome activation was used to trigger maturation and release of IL-1β in PBMCs. Specifically, isolated PBMCs from patients with hyperlipidemia at baseline and following 8 weeks of in vivo treatment with simvastatin (10-20 mg) daily were stimulated with lipopolysaccharide (LPS; 100 ng/mL) for 3 hours to induce proIL-Iβ expression followed by CC (2 mg/mL) stimulation for further 18 hours to activate the NLRP3 inflammasome complex to induce maturation/activation of IL-1β. Peripheral blood mononuclear cells were also isolated from healthy donors and stimulated in vitro with simvastatin (50, 25, 5, and 2 µmol/L) prior to stimulation with LPS and CC as described above. The effects of simvastatin treatment on levels of IL-1β expression were determined by enzyme-linked immunosorbent assay and western blot. Both in vitro and in vivo treatments with simvastatin led to a significant reduction in the levels of expression of IL-1β in response to stimulation with CC. Simvastatin inhibits the expression and activation of IL-1β induced by CC in PBMCs, which may contribute to its protective role in patients with cardiovascular disease.

scholarly journals Anti-lymphocyte globulin stimulates normal human T cells to proliferate and to release lymphokines in vitro. A study at the clonal level

Blood ◽  
1988 ◽  
Vol 72 (3) ◽  
pp. 956-963
Author(s):  
GC Barbano ◽  
A Schenone ◽  
S Roncella ◽  
R Ghio ◽  
A Corcione ◽  
...  
Keyword(s):  
T Cells ◽  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Interleukin 2 ◽  
Suppressor Cells ◽  
Peripheral Blood Mononuclear ◽  
Gm Csf ◽  
Recombinant Interleukin 2 ◽  
Macrophage Colony

Abstract Human peripheral blood mononuclear cells (PBMC) were stimulated in vitro with anti-lymphocyte globulin (ALG), and the phenotypic and functional properties of the blasts obtained were investigated. When stained with monoclonal antibodies (MoAbs), all of the blasts were identified as T cells that expressed predominantly the CD4 phenotype (70% of the cells). The remaining blasts were CD8+. These findings demonstrate that ALG stimulates both helper-inducer and cytotoxic- suppressor cells at random since the CD4 to CD8 ratio in the stimulated blasts was the same as in resting PBMC. This ratio is different from that observed in short-term cultures of T cells stimulated with phytohemagglutinin (PHA) under the same conditions (CD4 to CD8 ratio less than 1). ALG-stimulated T cells were cloned by limiting dilution in the presence of recombinant Interleukin-2 (rIL-2). The clones obtained were expanded and maintained in long term cultures with rIL-2. Thirty-two clones were tested for their capacity of producing colony stimulating activity (CSA) or burst promoting activity (BPA). Twenty- eight of them produced CSA and 12 produced BPA. No correlation was found between the surface phenotype and the ability of the clones to produce CSA or BPA (ie, both the CD4+ and CD8+ clones released the cytokines). When 16 of the same clones were tested for II-2 and gamma interferon (gamma IFN) production, 12 were found to be gamma INF and IL- 2 producers. All of the gamma IFN producers also released IL-2, whereas in the single clones no correlation was found with the capacity of releasing BPA and CSA. Supernatants from selected T-cell clones were also tested for hematopoietic growth factor activities in the presence of neutralizing antisera to human granulocyte-macrophage colony stimulating factor (GM-CSF) or to Interleukin-3 (IL-3). It was found that most CSA was attributable to GM-CSF, whereas BPA was mainly related to the presence of IL-3.

scholarly journals Induction of CD4+CD25+ Regulatory T Cells from In Vitro Grown Human Mononuclear Cells by Sparteine Sulfate and Harpagoside

Biology ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 211 ◽  
Author(s):  
Nour Z. Atwany ◽  
Seyedeh-Khadijeh Hashemi ◽  
Manju Nidagodu Jayakumar ◽  
Mitzi Nagarkatti ◽  
Prakash Nagarkatti ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Mononuclear Cells ◽  
Cultured Cells ◽  
Inflammatory Responses ◽  
Human Peripheral Blood ◽  
Stimulation Index ◽  
Tgf Beta ◽  
Peripheral Blood Mononuclear

Regulatory T cells (Tregs) are key players in the regulation of inflammatory responses. In this study, two natural molecules, namely, sparteine sulfate (SS) and harpagoside (Harp), were investigated for their ability to induce Tregs in human peripheral blood mononuclear cells (PBMCs). PBMCs were isolated from healthy volunteers and grown in the presence or absence of ConA, with TGF-beta, SS or Harp. Expression of the mRNA of FoxP3, TGF-beta, IL-10 and GAPDH was assessed via q-PCR. The expression of Treg markers including CD4, CD25, CD127 and FoxP3 was measured via flow cytometry. The secretion of IL-10 and TGF-beta by cultured cells was assessed by ELISA. Furthermore, the suppressive role of SS and Harp on PBMCs in vitro was tested via allogeneic mixed lymphocyte reaction (MLR). Data obtained show that both compounds increased the expression of FoxP3, TGF-beta and IL-10 mRNA in resting PBMCs but to a lesser extent in activated cells. Moreover, they significantly increased the percent of CD4+CD25+FoxP3+CD127− Tregs in activated and naïve PBMCs. Functionally, both compounds caused a significant reduction in the stimulation index in allogeneic MLR. Together, our data demonstrate for the first time that SS and Harp can induce human Tregs in vitro and therefore have great potential as anti-inflammatory agents.

Neopterin suppresses the activity of tryptophan-degrading enzyme indoleamine 2,3-dioxygenase in human peripheral blood mononuclear cells

Pteridines ◽  
2013 ◽  
Vol 24 (3) ◽  
pp. 237-243
Author(s):  
Sebastian Schroecksnadel ◽  
Elena-Sophia Ledjeff ◽  
Johanna Gostner ◽  
Christiana Winkler ◽  
Katharina Kurz ◽  
...  
Keyword(s):  
Peripheral Blood Mononuclear Cells ◽  
Peripheral Blood ◽  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Peripheral Blood Mononuclear ◽  
Indoleamine 2,3 Dioxygenase ◽  
Blood Mononuclear Cells ◽  
Ifn Γ

AbstractIn vitro, large amounts of neopterin are released from human monocyte-derived macrophages and dendritic cells primarily upon stimulation with Th1-type cytokine interferon-γ (IFN-γ). IFN-γ also induces the enzyme indoleamine 2,3-dioxygenase (IDO), which degrades tryptophan (TRP) to form kynurenine (KYN). IDO-mediated TRP catabolism is very effective in suppressing the proliferation of T lymphocytes as well as of pathogens in vitro and in vivo. In this study, we investigated whether exogenously added neopterin may influence IDO activity in resting and in stimulated peripheral blood mononuclear cells (PBMC). PBMC were isolated from healthy donors, and neopterin was added in a concentration range from 0.01 to 50 μmol/L. After 30 min, PBMC were stimulated or not with 10 μg/mL of mitogen phytohemagglutinin (PHA). After 48 h, culture supernatants were collected, KYN and TRP concentrations were measured by high-performance liquid chromatography, and the ratio of KYN vs. TRP was calculated as an estimate of IDO activity. Spontaneous as well as PHA-induced TRP breakdown was suppressed by exogenously added neopterin in a dose-dependent way; the lowest active concentration of neopterin was <100 nmol/L. As neopterin concentrations in the nanomolar range are commonly observed in patients suffering from infections, sepsis, or uremia, our results suggest that neopterin formation might also serve as a feedback mechanism to slow down TRP degradation in vivo.

scholarly journals Simian Immunodeficiency Virus SIVagm Efficiently Utilizes Non-CCR5 Entry Pathways in African Green Monkey Lymphocytes: Potential Role for GPR15 and CXCR6 as Viral Coreceptors

2015 ◽  
Vol 90 (5) ◽  
pp. 2316-2331 ◽  
Author(s):  
Nadeene E. Riddick ◽  
Fan Wu ◽  
Kenta Matsuda ◽  
Sonya Whitted ◽  
Ilnour Ourmanov ◽  
...  
Keyword(s):  
T Cells ◽  
Mononuclear Cells ◽  
Rhesus Macaques ◽  
Target Cells ◽  
Peripheral Blood Mononuclear ◽  
Immunodeficiency Virus ◽  
Sooty Mangabeys ◽  
Natural Hosts

ABSTRACTAfrican green monkeys (AGM) are natural hosts of simian immunodeficiency virus (SIV), and infection in these animals is generally nonpathogenic, whereas infection of nonnatural hosts, such as rhesus macaques (RM), is commonly pathogenic. CCR5 has been described as the primary entry coreceptor for SIVin vivo, while human-derived CXCR6 and GPR15 also appear to be usedin vitro. However, sooty mangabeys that are genetically deficient in CCR5 due to an out-of-frame deletion are infectible with SIVsmm, indicating that SIVsmm can use alternative coreceptorsin vivo. In this study, we examined the CCR5 dependence of SIV strains derived from vervet AGM (SIVagmVer) and the ability of AGM-derived GPR15 and CXCR6 to serve as potential entry coreceptors. We found that SIVagmVer replicated efficiently in AGM and RM peripheral blood mononuclear cells (PBMC) in the presence of the CCR5 antagonist maraviroc, despite the fact that maraviroc was capable of blocking the CCR5-tropic strains SIVmac239, SIVsmE543-3, and simian-human immunodeficiency virus SHIV-AD8 in RM PBMC. We also found that AGM CXCR6 and AGM GPR15, to a lesser extent, supported entry of pseudotype viruses bearing SIVagm envelopes, including SIVagm transmitted/founder envelopes. Lastly, we found that CCR5, GPR15, and CXCR6 mRNAs were detected in AGM and RM memory CD4+T cells. These results suggest that GPR15 and CXCR6 are expressed on AGM CD4+T cells and are potential alternative coreceptors for SIVagm usein vivo. These data suggest that the use of non-CCR5 entry pathways may be a common feature of SIV replication in natural host species, with the potential to contribute to nonpathogenicity in these animals.IMPORTANCEAfrican green monkeys (AGM) are natural hosts of SIV, and infection in these animals generally does not cause AIDS, whereas SIV-infected rhesus macaques (RM) typically develop AIDS. Although it has been reported that SIV generally uses CD4 and CCR5 to enter target cellsin vivo, other molecules, such as GPR15 and CXCR6, also function as SIV coreceptorsin vitro. In this study, we investigated whether SIV from vervet AGM can use non-CCR5 entry pathways, as has been observed in sooty mangabeys. We found that SIVagmVer efficiently replicated in AGM and RM peripheral blood mononuclear cells in the presence of the CCR5 antagonist maraviroc, suggesting that non-CCR5 entry pathways can support SIVagm entry. We found that AGM-derived GPR15 and CXCR6 support SIVagmVer entryin vitroand may serve as entry coreceptors for SIVagmin vivo, since their mRNAs were detected in AGM memory CD4+T cells, the preferred target cells of SIV.

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