Interferon-gamma Receptor Research Articles

Synergistic Activation of Inflammatory Cytokine Genes by Interferon-γ-Induced Chromatin Remodeling and Toll-like Receptor Signaling

Synergistic activation of inflammatory cytokine genes by interferon-γ (IFN-γ) and Toll-like receptor (TLR) signaling is important for innate immunity and inflammatory disease pathogenesis. Enhancement of TLR signaling, a previously proposed mechanism, is insufficient to explain strong synergistic activation of cytokine production in human macrophages. Rather, we found that IFN-γ induced sustained occupancy of transcription factors STAT1, IRF-1, and associated histone acetylation at promoters and enhancers at the TNF, IL6, and IL12B loci. This priming of chromatin did not activate transcription but greatly increased and prolonged recruitment of TLR4-induced transcription factors and RNA polymerase II to gene promoters and enhancers. Priming sensitized cytokine transcription to suppression by Jak inhibitors. Genome-wide analysis revealed pervasive priming of regulatory elements by IFN-γ and linked coordinate priming of promoters and enhancers with synergistic induction of transcription. Our results provide a synergy mechanism whereby IFN-γ creates a primed chromatin environment to augment TLR-induced gene transcription.

40: Myxomavirus-derived serpin prolongs survival and reduces vasculitis in lethal herpesviral infection in mice by modulating thrombotic factor X and inflammatory cytokine IL-10

Background Lethal viral infections produce widespread inflammation with vascular leakage, clotting and bleeding (DIC), and high mortality, up to 40–70% in disseminated viral infections. Treatment for sepsis and DIC remains very limited. Serine proteases in clot-forming (thrombotic) and clot-dissolving (thrombolytic) cascades are activated by a cytokine storm and also induce systemic inflammation. Host regulators of thrombosis and thrombolysis by serine proteases inhibitors (serpins) is lost. Serp-1 is a potent myxomavirus anti-inflammatory protein, which inhibits factor X (fX), tPA and uPA in vitro. Serp-1 reduces arterial inflammation and atherogenesis in many animal models and has been successfully tested in patients with unstable plaque and stent implants. Methods and results: Purified Serp-1 protein treatment significantly improved survival in lethal murine Gammaherpesvirus-68 (MHV68) infection in interferon gamma receptor (IFN γ R) knock-out mice ( N = 72 mice; P N = 30 mice; P = NS). Serp-1 reduced viral antigen, lung hemorrhage, and aortic, lung and colon inflammation in MHV68 infected mice. Neuroserpin suppressed a wide swath of immune cell responses, while Serp-1 selectively increased CD11c + splenocytes (macrophage and dendritic cells) and reduced CD11b + tissue macrophage. Serp-1 significantly reduced fX and increased IL-10 gene expression in the aorta and increased plasma IL-10 protein, whereas neuroserpin decreased IL-10. The fX inhibitor fondaparinux, when given alone, did not improve survival. However improved survival with Serp-1 treatment was lost after treatment with IL-10 receptor antibody immediately post infection ( N = 12 mice; P = 0.014). Conclusions: Serp-1, a unique myxomavirus-derived serpin, improves survival after lethal mouse herpesviral infection, reducing viral load, hemorrhage and arterial inflammation. Serp-1 provides a potential new therapeutic approach for lethal viral sepsis and DIC through modulation of FX and IL-10 activity.

194: IRF8 regulates autophagy and activates microglia to exacerbate neuroinflammation

IRF8 is a transcription factor of the IRF family expressed in macrophages and dendritic cells (DCs). It enhances type I interferon induction in pDCs and IL12p40 in CD8 + DCs and macrophages. We have observed that IRF8 regulates transcription of a series of genes in the autophagy pathway in macrophages and DCs in response to IFNg and toll-like receptor signaling, and plays a critical role in the formation of autophagosomes and their fusion with lysosomes. Recently, IRF8 was identified as a risk factor for several autoimmune diseases including multiple sclerosis (MS) in SNP based epidemiological studies. MS is a neuroinflammatory disease that involves activation and expansion of Th17, Th1 T cells as well as microglia, the antigen presenting cells of the central nervous system. Since the SNPs for MS lie in the 3′ noncoding regions of IRF8 , regulated expression of IRF8 likely accounts for its role in MS neuroinflammation. Because the mechanism by which IRF8 contributes to MS pathogenesis has not been clarified, we have undertaken in depth analysis of IRF8 activity in the mouse model of MS. Our results indicate that IRF8 plays a critical role at multiple steps of the disease, from the onset to progression in the periphery and the CNS, including activation and expansion of microglia during neuroinflammation. These observations are discussed in the context of its role in regulating autophagy.

Natural killer cell‐mediated contact sensitivity develops rapidly and depends on interferon‐α, interferon‐γ and interleukin‐12

Natural killer (NK) cell-mediated contact sensitivity was recently described in mice. Here, we confirm NK cell-mediated contact sensitivity (CS) in SCID and RAG1(-/-) mice but not in SCIDbeige mice, which have non-functional NK cells that lack NK cell granules. NK cell-mediated CS was transferred by liver mononuclear cells and the DX5(+) fraction of liver cells, confirming that NK cells mediate CS in the absence of T and B cells. Participation of NKT cells and B-1 cells was ruled out using Jα18(-/-) and JH(-/-) mice, respectively. Remarkably, NK cell-mediated CS was observed just 1hr after immunization and was detectable as early as 30min after challenge. Further, we examined cytokine requirements for NK cell-mediated CS, and found that liver mononuclear cells from interleukin-12(-/-) , interferon-γ(-/-) and interferon-α receptor(-/-) donors fail to transfer NK cell-mediated CS to naive hosts. Our studies clearly show that dinitrofluorobenzene sensitized NK cells mediate very rapid, antigen-specific cell-mediated immunity, with features of both innate and acquired immune responses.

IFN-γ and its receptors in a reptile reveal the evolutionary conservation of type II IFNs in vertebrates

In this study, interferon gamma (IFN-γ) and interferon gamma receptor (IFN-γR) genes have been identified in non-avian reptile, the North American green anole lizard (Anolis carolinensis). Like their counterparts from other jawed vertebrates, lizard IFN-γ, IFN-γR1 and IFN-γR2 show conserved features in genomic organizations, gene loci and protein sequences. The IFN-γ gene has the full cDNA sequence of 936bp, with 522bp open reading frame (ORF) encoding 174 amino acids, and has the genomic organization of four exons and three introns as observed in IFN-γ genes of other classes of vertebrates. The receptors, IFN-γR1 and IFN-γR2 have the ORF of 1278 and 984bp, coding for 425 and 327 aa, respectively, with the genome organization of seven exons and six introns. In the gene loci of IFN-γ, DYRK2, IL22, IL26 and MDM1 are found with conserved synteny in vertebrates, and similar genes adjacent to IFN-γR1 and IFN-γR2 were also found. These receptors also contain conserved motifs, such as the membrane-proximal region and the C-terminal five residue motif in IFN-γR1, and intracellular conservative sequence in IFN-γR2, which have been confirmed to mediate down-stream JAK-STAT signaling pathway in mammals. IFN-γ and its receptors, IFN-γR1 and IFN-γR2 were constitutively expressed in organs/tissues examined in the lizard, and up-regulated expression of IFN-γ was observed in organs/tissues examined following the poly(I:C) stimulation, suggesting its antiviral role in lizards. The conserved features of IFN-γ and its receptors, IFN-γR1 and IFN-γR2, in gene organization and gene locus as well as in functional domain or motif may imply that the function of type II IFN system is evolutionarily conserved in the green anole lizard, as observed in other classes of vertebrates.

Properties of Immature Myeloid Progenitors with Nitric-Oxide-Dependent Immunosuppressive Activity Isolated from Bone Marrow of Tumor-Free Mice

Myeloid derived suppressor cells (MDSCs) from tumor-bearing mice are important negative regulators of anti-cancer immune responses, but the role for immature myeloid cells (IMCs) in non-tumor-bearing mice in the regulation of immune responses are poorly described. We studied the immune-suppressive activity of IMCs from the bone marrow (BM) of C57Bl/6 mice and the mechanism(s) by which they inhibit T–cell activation and proliferation. IMCs, isolated from BM by high-speed FACS, inhibited mitogen-induced proliferation of CD4+ and CD8+ T-cells in vitro. Cell-to-cell contact of T-cells with viable IMCs was required for suppression. Neither neutralizing antibodies to TGFβ1, nor genetic disruption of indolamine 2,3-dioxygenase, abrogated IMC-mediated suppressive activity. In contrast, suppression of T-cell proliferation was absent in cultures containing IMCs from interferon-γ (IFN-γ) receptor KO mice or T-cells from IFN-γ KO mice (on the C57Bl/6 background). The addition of NO inhibitors to co-cultures of T-cells and IMC significantly reduced the suppressive activity of IMCs. IFN-γ signaling between T-cells and IMCs induced paracrine Nitric Oxide (NO) release in culture, and the degree of inhibition of T-cell proliferation was proportional to NO levels. The suppressive activity of IMCs from the bone marrow of tumor-free mice was comparable with MDSCs from BALB/c bearing mice 4T1 mammary tumors. These results indicate that IMCs have a role in regulating T-cell activation and proliferation in the BM microenvironment.

A Single Nucleotide Polymorphism within the Interferon Gamma Receptor 2 Gene Perfectly Coincides with Polledness in Holstein Cattle

Polledness is a high impact trait in modern milk and beef production to meet the demands of animal welfare and work safety. Previous studies have mapped the polled-locus to the proximal region of the bovine chromosome 1 (BTA1) and narrowed it down to approximately 1 Mb. Sequencing of the positional candidate genes within the 1 Mb polled region and whole genome sequencing of Holsteins revealed a single nucleotide polymorphism (SNP) AC000158: g.1390292G>A within intron 3 of the interferon gamma receptor 2 gene (IFNGR2) in perfect co-segregation with polledness in Holsteins. This complete association was validated in 443 animals of the same breed. This SNP allows reliable genotyping of horned, heterozygous and homozygous polled Holsteins, even in animals that could not be resolved using the previously published haplotype for Holstein.

Myxomavirus-Derived Serpin Prolongs Survival and Reduces Inflammation and Hemorrhage in an Unrelated Lethal Mouse Viral Infection

Lethal viral infections produce widespread inflammation with vascular leak, clotting, and bleeding (disseminated intravascular coagulation [DIC]), organ failure, and high mortality. Serine proteases in clot-forming (thrombotic) and clot-dissolving (thrombolytic) cascades are activated by an inflammatory cytokine storm and also can induce systemic inflammation with loss of normal serine protease inhibitor (serpin) regulation. Myxomavirus secretes a potent anti-inflammatory serpin, Serp-1, that inhibits clotting factor X (fX) and thrombolytic tissue- and urokinase-type plasminogen activators (tPA and uPA) with anti-inflammatory activity in multiple animal models. Purified serpin significantly improved survival in a murine gammaherpesvirus 68 (MHV68) infection in gamma interferon receptor (IFN-γR) knockout mice, a model for lethal inflammatory vasculitis. Treatment of MHV68-infected mice with neuroserpin, a mammalian serpin that inhibits only tPA and uPA, was ineffective. Serp-1 reduced virus load, lung hemorrhage, and aortic, lung, and colon inflammation in MHV68-infected mice and also reduced virus load. Neuroserpin suppressed a wide range of immune spleen cell responses after MHV68 infection, while Serp-1 selectively increased CD11c(+) splenocytes (macrophage and dendritic cells) and reduced CD11b(+) tissue macrophages. Serp-1 altered gene expression for coagulation and inflammatory responses, whereas neuroserpin did not. Serp-1 treatment was assessed in a second viral infection, mouse-adapted Zaire ebolavirus in wild-type BALB/c mice, with improved survival and reduced tissue necrosis. In summary, treatment with this unique myxomavirus-derived serpin suppresses systemic serine protease and innate immune responses caused by unrelated lethal viral infections (both RNA and DNA viruses), providing a potential new therapeutic approach for treatment of lethal viral sepsis.

Calculating Binding Free Energies of Variants of hIFN-gamma and their Extracellular Receptor

Cytokines play an important role in cellular communication and in modulation of the cellular immune responses. A computational protocol is presented that allows the prediction and analysis of the effect of particular mutations in the cytokine molecules on the interactions with their receptors. It is based on the theory developed by B. Jayaram and D. L. Beverige [1] and relies on collecting statistical data from molecular dynamics simulations.The protocol was first tested on a native cytokine – receptor complexes against experimental data such as association/dissociation constants or binding free energies on a particular cytokine – receptor system, namely the human interferon gamma (hIFNg) – human interferon gamma receptor (hIFNgR) complex.

Gamma Interferon Receptor Defect Presenting as Recurrent Tuberculosis

Failure of response to therapy in childhood tuberculosis may be due to resistance, paradoxical response or immunodeficiency. Interferon-γ (IFNγ) plays a major role during host defense against Mycobacterium tuberculosis (Mtb). An 8-y-old boy presented with fever, hepatosplenomegaly and parotid abscess. He had been earlier treated for BCG adenitis in infancy and at 5y for TB osteomyelitis of iliac bone and recovered. Investigations confirmed disseminated Mycobacterium Avium Intracellulare infection. He was investigated for immunodeficiency because of recurrent mycobacterial disease and a partial defect of γ-interferon receptor was identified. He required a 2y course of therapy with a 7 drug regimen and recovered. The authors report this case because of its rarity and to highlight the need to consider γ-interferon receptor defect in the presence of recurrent tuberculosis (TB) and also review the options for therapy.

Investigation of the expression of mediators of neovascularization from mononuclear leukocytes in thromboangiitis obliterans

The aim of this study was to investigate the expression of the cytokines, chemokines and effective molecules of peripheral blood mononuclear cells (PBMCs) that play a role in neovascularization in thromboangiitis obliterans (TAO). Lymphocytes from TAO patients (n = 20) and control subjects (healthy smokers [n = 16] and non-smokers [n = 17]) were evaluated using realtime polymerase chain reaction in order to examine the mRNA expression of CXCL1 and interleukin 8 (IL-8; inducers of collateral development by recruitment of circulating progenitor cells [CPCs]), endothelial cell growth factor A (VEGF-A) and inducible nitric oxide synthase (iNOS; inducers of angiogenesis) and interferon gamma (IFN-γ) and vascular endothelial growth factor receptor 1 (VEGFR-1; inhibitors of angiogenesis). CXCL1 expression was significantly higher in the TAO patients than control subjects. The expressions of IL-8, VEGFR-1 and IFN-γ were significantly higher in the TAO patients and smokers than in non-smokers. However, no differences in iNOS and VEGF-A expression were noted. In conclusion, PBMCs from TAO patients expressed cytokines that potentially recruit CPCs and promote arteriogenesis. However, TAO patients typically have low CPC levels, perhaps due to high oxidative stress. Further studies are recommended in order to investigate the efficacy of antioxidant therapy on the outcome of TAO before administration of angiogenic factors.

The clinical and genetic factors for predicting the response to inhaled corticosteroids

Background It has been reported that a part of asthma patients does not respond well to inhaled corticosteroids (ICS) and the benefit by long term treatment by high-dose ICS is limited in such patients. But the clinical or genetic factors for predicting ICS response have not been fully established especially in adults. The aim of this study is to establish the factor for predicting the response to ICS treatment. Method Patients treated only by ICS for more than 6 months were enrolled and classified into responder group (R group, n=30) if FEV1 improvement ≥ 5% and nonresponder group (NR group, n=40, FEV1 improvement <5%). The relationship between ICS response and pretreatment clinical indices and 21 single nucleotide polymorphism (SNP) were retrospectively analyzed. Results In R group, peripheral blood eosinophil % (R: NR = 7.5: 4.3%) and serum total IgE level (550.4: 497.1 U/ml) was significantly higher as compared to NR group. R group also showed significantly lower %VC (97.5: 114.8%), % FEV1.0 (77.9: 101.3%), FEV1.0% (67.5: 76.4%) and higher bronchial hyperresponsiveness. Bronchial reversibility test was available in 30 patients (R: n=11, NR: n=19) and reversibility was significantly higher in R group (15.9: 5.4%). By logistic multivariate analysis for those 30 patients, bronchial reversibility was significantly related to ICS response. SNP in IFN-g R1 L467P was also related to ICS response. Post/Pre FEV1 ratio was significantly higher in homo/ hetero group as compared to wild group (140.2 v.s 108.8%). Conclusion Pre-treatment bronchial reversibility was identified as a prediction factor for ICS response. It has been reported that SNP in IFN-gR is associated with allergic diseases and serum IgE level and the SNP might be potentially related to ICS response.

Abstract 329: Myxomavirus-derived Serpin Prolongs Survival and Reduces Vasculitis in MHV68 Infected Mice by Enhancing IL-10

Background Lethal viral infections produce widespread inflammation with vascular leaking, clotting and bleeding (DIC), and high mortality. Serine proteases in clot-forming (thrombotic) and clot-dissolving (thrombolytic) cascades are activated by a cytokine storm and also induce systemic inflammation. Normal host ser ine p roteases in hibitor ( serpin ) regulation is lost. Serp-1 is a potent myxomavirus anti-inflammatory protein, which inhibits factor X (fX), tPA and uPA in vitro . Serp-1 reduces arterial inflammation and atherogenesis in many animal models and has been successfully tested in patients with unstable plaque and stent implants. Methods and results Purified Serp-1 protein treatment significantly improved survival in lethal murine Gammaherpesvirus-68 (MHV68) infection in interferon gamma receptor (IFNγR) knock-out mice (N = 72 mice; P &lt; 0.02) when given for 10 up to 30 days after infection. Treatment with a mammalian serpin, neuroserpin, that inhibits only tPA and uPA, was ineffective (N = 30 mice; P = NS). Serp-1 reduced viral antigen, lung hemorrhage, and aortic, lung and colon inflammation in MHV68 infected mice. Neuroserpin suppressed a wide swath of immune cell responses, while Serp-1 selectively increased CD11c+ splenocytes (macrophage and dendritic cells) and reduced CD11b+ tissue macrophage. Serp-1 significantly increased the IL-10 gene expression in aorta and plasma protein, whereas neuroserpin decreased IL-10. Serp-1 mediated survival in MHV68 infected mice was lost after treatment with IL-10 receptor antibody immediately post infection (N = 12 mice; P =0.014). Conclusions Serp-1, a unique myxomavirus-deried serpin, improves survival after lethal mouse herpesviral infection, reduces viral load, hemorrhage and arterial inflammation. Serp-1 provides a potential new therapeutic approach for lethal viral sepsis and DIC through altered FX and IL-10.

T-bet: a key player in a novel type of B cell activation essential for effective viral clearance (P4333)

Abstract IgG2a is known to be the most efficient antibody isotype for viral clearance. Here we demonstrate a novel pathway of B cell activation, leading to IgG2a production, and involving synergistic stimulation via B cell antigen receptors, TLR7 and interferon-gamma receptors. This leads to induction of T-bet expression in B cells, driving their differentiation into age-associated B cells (ABCs). T-bet positive ABCs appear during anti-viral responses and produce high titers of anti-viral IgG2a antibodies which are critical for efficient viral clearance. The results thus demonstrate a previously unknown role for T-bet expression in B cells during viral infections. Moreover the appearance of ABCs during anti-viral responses and during autoimmunity suggests a possible link between these two processes.

Interferon Alpha Treatment of Patients with Impaired Interferon Gamma Signaling

Patients with deficiency in the interferon gamma receptor (IFN-γR) are unable to respond properly to IFN-γ and develop severe infections with nontuberculous mycobacteria (NTM). IFN-γ and IFN-α are known to signal through STAT1 and activate many downstream effector genes in common. Therefore, we added IFN-α for treatment of patients with disseminated mycobacterial disease in an effort to complement their IFN-γ signaling defect. We treated four patients with IFN-γR deficiency with adjunctive IFN-α therapy in addition to best available antimicrobial therapy, with or without IFN-γ, depending on the defect. During IFN-α treatment, ex vivo induction of IFN target genes was detected. In addition, IFN-α driven gene expression in patients' cells and mycobacteria induced cytokine response were observed in vitro. Clinical responses varied in these patients. IFN-α therapy was associated with either improvement or stabilization of disease. In no case was disease exacerbated. In patients with profoundly impaired IFN-γ signaling who have refractory infections, IFN-α may have adjunctive anti-mycobacterial effects.

The Adenosine-Dependent Angiogenic Switch of Macrophages to an M2-Like Phenotype is Independent of Interleukin-4 Receptor Alpha (IL-4Rα) Signaling

Murine macrophages are activated by interferon-γ (IFN-γ) and/or Toll-like receptor (TLR) agonists such as bacterial endotoxin (lipopolysaccharide [LPS]) to express an inflammatory (M1) phenotype characterized by the expression of nitric oxide synthase-2 (iNOS) and inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin (IL)-12. In contrast, Th2 cytokines IL-4 and IL-13 activate macrophages by inducing the expression of arginase-1 and the anti-inflammatory cytokine IL-10 in an IL-4 receptor-α (IL-4Rα)-dependent manner. Macrophages activated in this way are designated as "alternatively activated" (M2a) macrophages. We have shown previously that adenosine A2A receptor (A(2A)R) agonists act synergistically with TLR2, TLR4, TLR7, and TLR9 agonists to switch macrophages into an "M2-like" phenotype that we have termed "M2d." Adenosine signaling suppresses the TLR-dependent expression of TNF-α, IL-12, IFN-γ, and several other inflammatory cytokines by macrophages and induces the expression of vascular endothelial growth factor (VEGF) and IL-10. We show here using mice lacking a functional IL-4Rα gene (IL-4Rα(-/-) mice) that this adenosine-mediated switch does not require IL-4Rα-dependent signaling. M2d macrophages express high levels of VEGF, IL-10, and iNOS, low levels of TNF-α and IL-12, and mildly elevated levels of arginase-1. In contrast, M2d macrophages do not express Ym1, Fizz1 (RELM-α), or CD206 at levels greater than those induced by LPS, and dectin-1 expression is suppressed. The use of these markers in vivo to identify "M2" macrophages thus provides an incomplete picture of macrophage functional status and should be viewed with caution.

Gain-of-function STAT1 mutations are associated with PD-L1 overexpression and a defect in B-cell survival

Gain-of-function STAT1 mutations are associated with PD-L1 overexpression and a defect in B-cell survival

IL1B, IL4R, IL12RB1 and TNF gene polymorphisms are associated with Plasmodium vivax malaria in Brazil

BackgroundMalaria is among the most prevalent parasitic diseases worldwide. In Brazil, malaria is concentrated in the northern region, where Plasmodium vivax accounts for 85% disease incidence. The role of genetic factors in host immune system conferring resistance/susceptibility against P. vivax infections is still poorly understood.MethodsThe present study investigates the influence of polymorphisms in 18 genes related to the immune system in patients with malaria caused by P. vivax. A total of 263 healthy individuals (control group) and 216 individuals infected by P. vivax (malaria group) were genotyped for 33 single nucleotide polymorphisms (SNPs) in IL1B, IL2, IL4, IL4R, IL6, IL8, IL10, IL12A, IL12B, IL12RB1, SP110, TNF, TNFRSF1A, IFNG, IFNGR1, VDR, PTPN22 and P2X7 genes. All subjects were genotyped with 48 ancestry informative insertion-deletion polymorphisms to determine the proportion of African, European and Amerindian ancestry. Only 13 SNPs in 10 genes with differences lower than 20% between cases and controls in a Poisson Regression model with age as covariate were further investigated with a structured population association test.ResultsThe IL1B gene -5839C > T and IL4R 1902A > G polymorphisms and IL12RB1 -1094A/-641C and TNF -1031 T/-863A/-857 T/-308 G/-238 G haplotypes were associated with malaria susceptibility after population structure correction (p = 0.04, p = 0.02, p = 0.01 and p = 0.01, respectively).ConclusionPlasmodium vivax malaria pathophysiology is still poorly understood. The present findings reinforce and increase our understanding about the role of the immune system in malaria susceptibility.

Polymorphisms Within the Promoter Region of the Gamma Interferon (IFN-γ) Receptor1 Gene are Associated With the Susceptibility to Chronic HBV Infection in an Iranian Population

Backgroundchronic hepatitis B virus (HBV) infection is a multifactorial disease that can result in serious clinical complications. Host genetic background especially the genes that encode immunologic factors like INF-γ and its receptor (IFN-γ R) are critical in the pathogenesis of infection.ObjectivesThe current study aimed to investigate the association between two single nucleotide polymorphisms (SNPs) at positions -611 and -56 within the promoter region of gamma interferon receptor1 gene (IFN-γ R1) and chronic HBV infection.Materials and MethodsGenomic DNA from peripheral blood samples of 200 chronically HBV infected patients and 200 healthy blood donors, as controls, were collected and genomic DNA was extracted by phenol-chloroform method and DNA analysis genotype identification was performed by PCR-RFLP.ResultsThe results indicated that both SNP’s frequency had a significant difference in the patient and control groups. At position -56, TT genotype was associated with patient group and P value was 0.002 and at position -611, GG genotype was further observed in control group and P value was 0.006.ConclusionsPresence of G allele at position -611 within promoter of IFN-γ R1 gene in the enrolled population for the study was related to lower risk of disease, and presence of T allele at position -56 was also related to susceptibility to chronic HBV infection. Men had higher frequency of chronic HBV infection, which might be the result of high risk behavior.

Interruption of IFNγR Signaling Results in Altered T Cell Trafficking in Vivo and Abrogation of GvHD While Maintaining a Robust Gvl Response

Abstract 455Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only curative treatment for patients with relapsed/refractory leukemia, and marrow failure states such as myelodysplasia and aplastic anemia. However, allo-HSCT is complicated by allogeneic donor T cell-mediated graft-versus-host disease (GvHD) which can be life-threatening especially in recipients of unrelated or HLA-mismatched hematopoietic stem cell products. These same alloreactive donor T cells also mediate a beneficial graft-versus-leukemia (GvL) effect. Thus, the clinical goal in allo-HSCT is to minimize GvHD while maintaining GvL. Recent studies have suggested that this might be achieved by infusing regulatory T cells (Tregs) which in some preclinical models suppress GvHD-causing alloreactive donor T cells but have only limited effects on GvL-promoting alloreactive donor T cells. Unfortunately, Tregs exist in low frequency in the peripheral blood, are costly to purify and expand, and after expansion are difficult to isolate due to the lack of cell surface markers, all of which prevent their routine use in the clinic. Thus, alternative therapeutic approaches that do not require Tregs are needed.We have found that interferon gamma receptor deficient (IFNγR−/−) allogeneic donor T cells induce significantly less GvHD in both a MHC fully-mismatched (B6 (H-2b) → Balb/c (H-2d)) and a minor-mismatched (B6 (H-2b) → B6×129(H-2b)) allo-HSCT models compared to WT T cells. In addition, IFNγR−/− donor T cells maintain a beneficial GvL effect, which has been examined in both systemic leukemia and solid tumor models using luciferase-expressing A20 cells derived from Balb/c. We find that IFNγR−/− T cells migrate primarily to the spleen while WT T cells to GI tract and peripheral lymph nodes (LNs) using bioluminescence imaging (BLI), suggesting that altered T cell trafficking of IFNγR−/− T cells to GvHD target organs might be the major reason for the reduced GvHD. We further demonstrate that the IFNγR-mediated signaling in alloreactive donor T cells is required for expression of CXCR3 which has been implicated in trafficking of T cells to areas of inflammation and target organs, commonly known to be the sites of GvHD. Indeed, CXCR3−/− T cells recapitulate the reduced GvHD potential of IFNγR−/− T cells. In addition, forced overexpression of CXCR3 in IFNγR−/− T cells via retroviral transduction partially rescues the GvHD defect observed in IFNγR−/− T cells. We next examine if inhibition of IFNγR signaling using a small molecule inhibitor can recapitulate the anti-GVHD effects seen in IFNγR−/− T cells. We find that INCB018424, an inhibitor of JAK1/JAK2 which are the mediators of IFNγR signaling, blocks CXCR3 expression in vitro. Most importantly, in vivo administration of INCB018424 after allo-HSCT alters T cell trafficking and significantly reduces GvHD. Thus, the IFNγR signaling pathway represents a promising therapeutic target for future efforts to mitigate GvHD while maintaining GvL after allo-HSCT. Moreover, this pathway can be exploited in other diseases besides GvHD such as those from organ transplantation, chronic inflammatory diseases and autoimmune diseases. Disclosures:DiPersio:genzyme: Honoraria.