A functional type I interferon pathway drives resistance to cornea herpes simplex virus type 1 infection by recruitment of leukocytes

Type I interferons are critical antiviral cytokines produced following herpes simplex virus type-1 （HSV-1） infection that act to inhibit viral spread. In the present study, we identify HSV-infected and adjacent uninfected corneal epithelial cells as the source of interferon-a. We also report mice deficient in the A1 chain of the type I IFN receptor （CDl18-/） are extremely sensitive to ocular infection with low doses （100 PFU） of HSV-1 as seen by significantly elevated viral titers in the cornea Compared to wild type （WT） controls. The enhanced susceptibil- ity correlated with a loss of CD4＋ and CD8＋ T cell recruitment and aberrant chemokine production in the cornea despite mounting an adaptive immune response in the draining mandibular lymph node of CDll8/ mice. Taken together, these results highlight the importance of IFN production in both the innate immune response as well as eliciting chemokine production required to facilitate adaptive immune cell trafficking.

PLP2, a potent deubiquitinase from murine hepatitis virus, strongly inhibits cellular type I interferon production

由象严重急性呼吸症候群(SARS ) 那样的 coronaviruses 的感染 coronavirus (SCoV ) 和老鼠肝炎病毒 A59 (MHV-A59 ) 导致很小的类型我干扰素(IFN ) 生产由招待细胞，它为与 SARS 联系的快速的病毒的生长和严重 immunopathology 潜在地负责。然而，为在感染 coronaviruses 的房间的低 IFN 生产的分子的机制仍然保持不清楚。这里，我们提供证据象 Papain 一样朊酶领域 2 (PLP2 ) ， nonstructural 蛋白质的一个催化领域 3 (nsp3 ) MHV-A59，能绑在 IRF3，引起它的 deubiquitination 并且阻止它的原子 translocation。作为后果， PLP2 的合作表示强烈禁止 CARDIF- ，调停 TBK1 、调停 IRF3 的 IFN 记者活动。另外，我们显示出那野类型的 PLP2 然而并非缺乏 deubiquitinase 的变异的 PLP2 (称) 活动能减少感应的 IFN 并且在感染 VSV 的房间支持病毒的生长。因此，我们的学习揭开了一病毒称它 coronaviruses 可以使用逃离主人天生的抗病毒的回答。

The host type I interferon response to viral and bacterial infections

Type I interferons (IFN) are well studied cytokines with anti-viral and immune-modulating functions. Type I IFNsare produced following viral infections, but until recently, the mechanisms of viral recognition leading to IFN productionwere largely unknown. Toll like receptors (TLRs) have emerged as key transducers of type I IFN during viral infectionsby recognizing various viral components. Furthermore, much progress has been made in defining the signaling path-ways downstream of TLRs for type I IFN production. TLR7 and TLR9 have become apparent as universally importantin inducing type I IFN during infection with most viruses, particularly by plasmacytoid dendritic cells. New intracellularviral pattern recognition receptors leading to type I IFN production have been identified. Many bacteria can also inducethe up-regulation of these cytokines. Interestingly, recent studies have found a detrimental effect on host cells if type IIFN is produced during infection with the intracellular gram-positive bacterial pathogen, Listeria monocytogenes. Thisreview will discuss the recent advances made in defining the signaling pathways leading to type I IFN production.

African swine fever virus S273R protein antagonizes type I interferon production by interfering with TBK1 and IRF3 interaction

African swine fever(ASF)is originally reported in East Africa as an acute hemorrhagic fever.African swine fever virus(ASFV)is a giant and complex DNA virus with icosahedral structure and encodes a variety of virulence factors to resist host innate immune response.S273R protein(pS273R),as a SUMO-1 specific cysteine protease,can affect viral packaging by cutting polymeric proteins.In this study,we found that pS273R was an important antagonistic viral factor that suppressed cGAS-STING-mediated type I interferon(IFN-I)production.A detailed analysis showed that pS273R inhibited IFN-I production by interacting with interferon regulatory factor 3(IRF3).Subsequently,we showed that pS273R disrupted the association between TBK1 and IRF3,leading to the repressed IRF3 phosphorylation and dimerization.Deletion and point mutation analysis verified that pS273R impaired IFN-I production independent of its cysteine protease activity.These findings will help us further understand ASFV pathogenesis.

Estrogen receptorα-mediated signaling inhibits type I interferon response to promote breast carcinogenesis

Estrogen receptorα(ERα)is an important driver and therapeutic target in∼70%of breast cancers.How ERαdrives breast carcinogenesis is not fully understood.In this study,we show that ERαis a negative regulator of type I interferon(IFN)response.Activation of ERαby its natural ligand estradiol inhibits IFN-β-induced transcription of downstream IFN-stimulated genes(ISGs),whereas ERαdeficiency or the stimulation with its antagonist fulvestrant has opposite effects.Mechanistically,ERαinduces the expression of the histone 2A variant H2A.Z to restrict the engagement of the IFN-stimulated gene factor 3(ISGF3)complex to the promoters of ISGs and also interacts with STAT2 to disrupt the assembly of the ISGF3 complex.These two events mutually lead to the inhibition of ISG transcription induced by type I IFNs.In a xenograft mouse model,fulvestrant enhances the ability of IFN-βto suppress ERα^(+)breast tumor growth.Consistently,clinical data analysis reveals that ERα^(+)breast cancer patients with higher levels of ISGs exhibit higher long-term survival rates.Taken together,our findings suggest that ERαinhibits type I IFN response via two distinct mechanisms to promote breast carcinogenesis.

Ebola virus VP35 perturbs type I interferon signaling to facilitate viral replication

As one of the deadliest viruses,Ebola virus(EBOV)causes lethal hemorrhagic fevers in humans and nonhuman primates.The suppression of innate immunity leads to robust systemic virus replication of EBOV,leading to enhanced transmission.However,the mechanism of EBOV-host interaction is not fully understood.Here,we identified multiple dysregulated genes in early stage of EBOV infection through transcriptomic analysis,which are highly clustered to Jak-STAT signaling.EBOV VP35 and VP30 were found to inhibit type I interferon(IFN)signaling.Moreover,exogenous expression of VP35 blocks the phosphorylation of endogenous STAT1,and suppresses nuclear translocation of STAT1.Using serial truncated mutations of VP35,N-terminal 1–220amino acid residues of VP35 were identified to be essential for blocking on type I IFN signaling.Remarkably,VP35 of EBOV suppresses type I IFN signaling more efficiently than those of Bundibugyo virus(BDBV)and Marburg virus(MARV),resulting in stable replication to facilitate the pathogenesis.Altogether,this study enriches understanding on EBOV evasion of innate immune response,and provides insights into the interplay between filoviruses and host.

Mechanism of inhibiting type I interferon induction by hepatitis B virus X protein

Hepatitis B virus(HBV)is regarded as a stealth virus,invading and replicating efficiently in human liver undetected by host innate antiviral immunity.Here,we show that type I interferon(IFN)induction but not its downstream signaling is blocked by HBV replication in HepG2.2.15 cells.This effect may be partially due to HBV X protein(HBx),which impairs IFNβpromoter activation by both Sendai virus(SeV)and components implicated in signaling by viral sensors.As a deubiquitinating enzyme(DUB),HBx cleaves Lys63-linked polyubiquitin chains from many proteins except TANK-binding kinase 1(TBK1).It binds and deconjugates retinoic acid-inducible gene I(RIG I)and TNF receptor-associated factor 3(TRAF3),causing their dissociation from the downstream adaptor CARDIF or TBK1 kinase.In addition to RIG I and TRAF3,HBx also interacts with CARDIF,TRIF,NEMO,TBK1,inhibitor of kappa light polypeptide gene enhancer in B-cells,kinase epsilon(IKKi)and interferon regulatory factor 3(IRF3).Our data indicate that multiple points of signaling pathways can be targeted by HBx to negatively regulate production of type I IFN.

SUMOylation of RIG-I positively regulates the type I interferon signaling

Retinoic acid-inducible gene-I(RIG-I)functions as an intracellular pattern recognition receptor(PRR)that recognizes the 5'-triphosphate moiety of single-stranded RNA viruses to initiate the innate immune response.Previous studies have shown that Lys63-linked ubiquitylation is required for RIG-I activation and the downstream anti-viral type I interferon(IFN-I)induction.Herein we reported that,RIG-I was also modified by small ubiquitin-like modifier-1(SUMO-1).Functional analysis showed that RIG-I SUMOylation enhanced IFN-I production through increased ubiquitylation and the interaction with its downstream adaptor molecule Cardif.Our results therefore suggested that SUMOylation might serve as an additional regulatory tier for RIG-I activation and IFN-I signaling.

PTEN-L promotes type I interferon responses and antiviral immunity

Phosphatase and tensin homolog deleted on chromosome ten(PTEN)is a well-known tumor suppressor that acts as a dual-specificity phosphatase and is frequently mutated in human cancer.Our previous work has demonstrated that PTEN also plays a vital role in type I interferon responses and antiviral innate immunity.Recently,a translational variant of PTEN with a long N-terminal extension(PTEN-L)has been discovered that is secreted into the extracellular environment and enters recipient cells,where it exerts a phosphatase function antagonistic to PI3K/Akt signaling and tumorigenesis.In this study,we demonstrate that PTEN-L promotes type I interferon responses and antiviral innate immunity during viral infection in a phosphatase activity-dependent manner.Compared with canonical PTEN,PTEN-L also exerts its antiviral function when it is applied exogenously in protein form.This finding was confirmed in cell cultures and mouse infection models.Furthermore,PTEN-L enhances the responses of both type I interferon and proinflammatory cytokines,thus suggesting that PTEN-L might possess additional functions compared with those of PTEN.Thus,the antiviral function of PTEN-L may open an avenue for the use of PTEN-L in antiviral therapy,particularly in patients with PTEN-deficient tumors.

Relevance of placental type I interferon beta regulation for pregnancy success

Pregnancy is a unique immunologic and microbial condition that requires an adequate level of awareness to provide a fast and protective response against pathogens as well as to maintain a state of tolerance to paternal antigens.Dysregulation of inflammatory pathways in the placenta triggered by pathogens is one of the main factors responsible for pregnancy complications.Type I IFNs are key molecules modulating immune responses at the level of the placenta and are crucial for protection of the pregnancy via their antiviral and immune modulatory properties.In this study,we elucidate the mechanisms controlling the basal expression of IFNβand its negative feedback.Using in vitro and in vivo animal models,we found that TLR signaling maintains basal IFNβlevels through the TLR4-MyD88-independent TBK/IRF3 signaling pathway.We describe the role of the TAM receptor Axl in the regulation of IFNβfunction in human and mouse trophoblast cells.The absence of TAM receptors in vivo is associated with fetal demise due to dysregulation of IFNβexpression and its pro-apoptotic downstream effectors.Collectively,our data describe a feedback signaling pathway controlling the expression and function of IFNβin the trophoblast that is essential for an effective response during viral and microbial infections.

Oncolytic Activity of Wild-type Newcastle Disease Virus HK84 Against Hepatocellular Carcinoma Associated with Activation of Type I Interferon Signaling

Background and Aims:Hepatocellular carcinoma(HCC)is listed as one of the most common causes of cancer-related death.Oncolytic therapy has become a promising treatment because of novel immunotherapies and gene editing technology,but biosafety concerns remain the biggest limitation for clinical application.We studied the the antitumor activity and biosafety of the wild-type Newcastle disease virus HK84 strain(NDV/HK84)and 10 other NDV strains.Meth-ods:Cell proliferation and apoptosis were determined by cell counting Kit-8 and fluorescein isothiocyanate Annexin V apoptosis assays.Colony formation,wound healing,and a xenograft mouse model were used to evaluate in vivo and in vitro oncolytic effectiveness.The safety of NDV/HK84 was tested in nude mice by an in vivo luciferase imaging system.The replication kinetics of NDV/HK84 in normal tis-sues and tumors were evaluated by infectious-dose assays in eggs.RNA sequencing analysis was performed to explore NDV/HK84 activity and was validated by quantitative real-time PCR.Results:The cell counting Kit-8 assays of vi-ability found that the oncolytic activity of the NDV strains differed with the multiplicity of infection(MOI).At an MOI of 20,the oncolytic activity of all NDV strains except the DK/JX/21358/08 strain was>80%.The oncolytic activities of the NDV/HK84 and DK/JX/8224/04 strains were>80%at both MOI=20 and MOI=2.Only NDV/HK84 had>80%oncolytic activities at both MOI=20 and MOI=2.We chose NDV/HK84 as the candidate virus to test the oncolytic effect of NDV in HCC in the in vitro and in vivo experiments.NDV/HK84 killed human SK-HEP-1 HCC cells without affecting healthy cells.Conclusions:Intratumor infection with NDV/HK84 strains compared with vehicle controls or positive controls indicated that NDV/HK84 strain specifically inhib-ited HCC without affecting healthy mice.High-throughput RNA sequencing showed that the oncolytic activity of NDV/HK84 was dependent on the activation of type I interferon signaling.

Emerging mechanisms and implications of c GAS-STING signaling in cancer immunotherapy strategies

The intricate interplay between the human immune system and cancer development underscores the central role of immunotherapy in cancer treatment.Within this landscape,the innate immune system,a critical sentinel protecting against tumor incursion,is a key player.The cyclic GMP-AMP synthase(c GAS)and stimulator of interferon genes(STING)pathway has been found to be a linchpin of innate immunity:activation of this signaling pathway orchestrates the production of type I interferon(IFN-α/β),thus fostering the maturation,differentiation,and mobilization of immune effectors in the tumor microenvironment.Furthermore,STING activation facilitates the release and presentation of tumor antigens,and therefore is an attractive target for cancer immunotherapy.Current strategies to activate the STING pathway,including use of pharmacological agonists,have made substantial advancements,particularly when combined with immune checkpoint inhibitors.These approaches have shown promise in preclinical and clinical settings,by enhancing patient survival rates.This review describes the evolving understanding of the c GAS-STING pathway's involvement in tumor biology and therapy.Moreover,this review explores classical and non-classical STING agonists,providing insights into their mechanisms of action and potential for optimizing immunotherapy strategies.Despite challenges and complexities,the c GAS-STING pathway,a promising avenue for enhancing cancer treatment efficacy,has the potential to revolutionize patient outcomes.

Higher Type 1 Interferon Levels in Plasma of Asymptomatic HIV-2 than in HIV-1 Individuals

A number of cytokines are secreted during HIV infection that enhances both innate and adaptive immune responses. Interferon-α/β/γ, IL-12, IL-15 and IL-18 have been found to contribute to the development, maturation, differentiation and function of NK and other immune cells. The levels of IFN-α/β/γ, IL-12, IL-15 and IL-18 were compared in the plasma of 90 HIV-1 infected and 90 HIV-2 infected subjects by ELISA or Cytometric Beads Array assays. The HIV-infected subjects were stratified according to CD4+ T cell counts into three groups: >500, 200 - 500 and <200 cells/ul, with 30 subjects in each group. Cytokine levels were also determined in the plasma of 50 HIV uninfected blood bank donors. Among the cytokines tested, IFN-α was found to be significantly increased in HIV-2 infected compared to HIV-1 infected subjects at high CD4+ T cell counts (p = 0.001). The levels of IFN-β were seen to differ between the two infections in patients from the category of medium CD4+ T cell counts: this was significantly increased in HIV-2 infected patients (p < 0.001) as well as compared to uninfected controls (p = 0.001). The levels of IFN-γ were similar at all the CD4+ T cell categories except for an increase in HIV-2 infected patients at low CD4+ T cell counts (p = 0.02). The levels of these cytokines were similar in all HIV-1 subjects. Also, the level of IL-12p70 was similar between the two infections but significantly higher in HIV-2 at low compared to medium CD4+ T cells categories (p = 0.047). Similar to IFN-γ and IL-12p70, the levels of both IL-18 and IL-15 were found to be significantly higher in HIV-2 infected patients compared to HIV-1 at low CD4+ T cell counts (p < 0.05). These data show that there is variability in the levels of innate cytokines at different stages of HIV infection but the finding of increased IFN-α in HIV-2 infected asymptomatic subjects is consistent with the high innate NK responses previously noted at this stage of infection.

TRIM4 modulates type I interferon induction and cellular antiviral response by targeting RIG-I for K63-1inked ubiquitination

RIG-I 是认出病毒的 RNA 的不同种类的一个枢轴的细胞质的传感器。这识别导致抄写因素 NF-B 和 IRF3，它协作导致打的 activationof 我干扰素(IFN ) 和天生的抗病毒的 response.In 这研究，我们作为 RIG-I-mediated IFN 的一个积极管理者识别了整齐的家庭蛋白质 TRIM4 感应。Overexpressionof TRIM4 加强了 IRF3 和 NF-B 的被触发病毒的激活，以及 IFN- 正式就职，而 TRIM4had 相反的效果击倒。机械学地， TRIM4 与 RIG-I 联系并且为连接 K63 的 polyubiquitination 指向它。我们 TRIM4 是由调停的导致病毒的 IFN 正式就职小径的一个重要管理者的 findingsdemonstrate 为 K63-linkedubiquitination 的 RIG-I。

Involvement of Dectin-2 in the Innate Inflammatory Response Triggered by Influenza Virus Hemagglutinin

C-type lectin receptors (CLRs) are representative pattern recognition receptors that recognize microbial polysaccharides expressed on antigen-presenting cells. In the present study, we carried out further detailed analysis on the involvement of Dectin-2, a CLR that senses high mannose polysaccharide, in innate immune responses induced by influenza virus hemagglutinin (HA). Treatment of HA with periodate or PNGase F induced lower interleukin (IL)-12p40 secretion by conventional dendritic cells (DCs) compared with the untreated group. In contrast, treatment with O-glycosidase did not affect cytokine production. Green fluorescent protein expression in canonical Dectin-2-transducing cells was approximately 3% - 12% following HA stimulation, except with the A/H1N1pdm09 subtype HA. This expression was markedly reduced in cells possessing mutated amino acids in the carbohydrate recognition domain of Dectin-2, especially following stimulation with HA derived from the A/H3N2 subtype. Interferon (IFN)-α production from CD11c+Siglec-H+PDCA-1+ plasmacytoid DCs was significantly increased in Dectin-2 knockout mice compared with wild-type mice upon stimulation with HA except for the B/Yamagata lineage HA. These results suggested that Dectin-2 is involved in initiating inflammatory responses via mannose polysaccharide on HA. However, other mechanisms may function in the antiviral response, including the type I IFN axis.

TRIM37对猪繁殖与呼吸综合征病毒复制及IFN-β产生影响的研究

本实验室前期通过质谱分析筛选到宿主因子三方基序蛋白37(TRIM37),推测其可能与猪繁殖与呼吸综合征病毒(PRRSV)的复制相关。为探究TRIM37对PRRSV复制的影响,本研究将不同剂量的PRRSV HN07-1株(MOI分别为0.01、0.1、1)分别感染猪肺泡巨噬细胞(PAM)和MARC-145细胞后不同时间(6 h、12 h、24 h、36 h和48 h),采用荧光定量PCR(qPCR)检测细胞中内源TRIM37的转录水平,结果显示PRRSV能够刺激这两种细胞内源TRIM37的转录,并且PRRSV以MOI 1及感染后24 h细胞中TRIM37的转录水平最高,感染后36 h和48 h细胞中TRIM37的转录水平较感染后24 h有所下降但仍显著高于对照组(P<0.05)。从MARC-145细胞中经PCR扩增TRIM37基因并克隆至pCAGGS-HA中构建真核表达质粒pCAGGS-HA-TRIM37,经双酶切及测序鉴定正确后转染MARC-145细胞,24 h后以MOI 1将HN07-1株感染细胞,感染后不同时间分别采用qPCR、western blot、病毒滴度(TCID50)测定和间接免疫荧光试验(IFA)检测PRRSV的复制情况。结果显示,与转染空载体pCAGGS-HA的对照细胞相比,过表达TRIM37后细胞中PRRSV ORF7的转录水平、N蛋白的表达水平(感染后48 h和72 h)及病毒滴度(感染后36 h与48 h)均显著(P<0.05)或者极显著(P<0.01)下降。针对TRIM37基因设计3对特异性的TRIM37 siRNA-1/2/3,转染MARC-145细胞后,利用qPCR检测TRIM37 siRNA的干扰效率,结果显示,TRIM37 siRNA-2能够有效降低TRIM37的转录水平。将TRIM37 siRNA-2转染MARC-145细胞后再以MOI 1 HN07-1株感染,感染后不同时间分别采用qPCR、western blot和病毒滴度(TCID50)测定检测PRRSV的复制情况。结果显示,与转染NC siRNA的对照细胞相比,干扰TRIM37表达的细胞中PRRSV ORF7的转录水平、N蛋白的表达水平及病毒滴度均显著(P<0.05)或极显著(P<0.01)升高。进一步将不同剂量的pCAGGS-HA-TRIM37与报告质粒pRL-TK-Luc和pIFN-β-Luc共转染HEK293T细胞;同时将不同剂量的pCAGGS-HA-TRIM37与报告质粒pRL-TK-Luc和pISRE-Luc共转染HEK293T细胞,18 h后加入poly(I:C)处理上述各组细胞,6 h后利用双荧光素酶试剂盒检测各组细胞中IFN-β和ISRE启动子的活性。将pCAGGS-HA-TRIM37转染HEK293T细胞,18 h后加入poly(I:C)处理细胞,6 h后采用qPCR检测细胞中相关干扰素刺激基因(ISG)(ISG15、CXCL10、MX1和OAS1)相对转录水平。双荧光素酶试验结果显示,与转染空载体的对照细胞相比,过表达TRIM37显著上调细胞中poly(I:C)激活的IFN-β和ISRE启动子的活性(P<0.05),且这种上调作用具有剂量依赖性。qPCR结果显示,与转染空载体的对照细胞相比,过表达TRIM37显著上调细胞中poly(I:C)激活的ISG15、CXCL10、MX1和OAS1 mRNA的转录水平(P<0.05)。本研究首次表明TRIM37能够通过促进细胞中相应干扰素的表达抑制PRRSV复制,该结果丰富了病毒感染过程中PRRSV-宿主相互作用的网络和机制,深化了对PRRSV致病机制的认知。

cGAS-STING通路异常激活及其抑制剂在免疫和炎症疾病中的研究进展

cGAS-STING通路是针对多种类型病原体进行免疫防御的主要途径之一,环鸟苷酸-腺苷酸合成酶(cGAS)通过识别细胞质的DNA分子,催化生成第二信使cGAMP(cyclic GMP-AMP)与干扰素基因刺激因子(STING)结合,诱导产生I型干扰素(IFN-I),激活机体先天免疫系统。cGAS-STING通路的适当激活有助于机体实现自我保护,因此,近年来STING激动剂在肿瘤免疫治疗的研究中引起了广泛关注,一些候选药物已进入临床研究,用于多种肿瘤治疗。与此同时,cGAS-STING通路异常激活会导致自身免疫性疾病的发生,获得了药物研究者的广泛关注并积极开发其抑制剂。该文总结了cGAS-STING通路的机制和调控位点,概述了cGAS-STING通路相关的免疫和炎症疾病及其抑制剂的研究进展。

Cytokine gene expression in human hepatocytes infected with dengue virus serotype 3 (strain-16562)

Liver is a site of viral replication and liver dysfunction is a characteristic of severe dengue infection. To understand these mechanisms, we analyzed the response of a hepatic cell linage, HepG2 to infection with dengue 3 virus (strain 16562). Steady state levels of mRNA accumulation were assessed for 14 genes involved in modulation of the host immune responses, at 6, 24 and 48 hpi, by quantitative reverse transcription real-time PCR (qRT-PCR). Fourteen genes showed altered expression upon infection with D3V including;cytokines/chemokines (IL-1β, IL-6, IL-8, RANTES, MCP-2, IL-2Rα and TGF-βIIIR), type I interferon (IFN-α and IFN-β), and pattern-recognition receptors (TLR3, TLR8, RIG-1, MDA5 and MyD88). Although these genes are associated with mechanism of innate immune response and anti-viral activity, their altered expression does not inhibit D3V (strain 16562) growth kinetics and virus yield in HepG2 cells. Gene expression in liver may explain pathological changes associated with dengue virus infection.

狂犬病病毒强、弱毒株糖蛋白调节Ⅰ型干扰素作用的差异分析

【目的】狂犬病(Rabies)是由狂犬病病毒(Rabies virus,RABV)引起的一种高致死性人兽共患传染病。Ⅰ型干扰素(IFN-I)通路在抵抗RABV感染中发挥重要作用。RABV可通过磷蛋白及核蛋白的功能逃逸IFN-I的抗病毒作用,本研究旨在探讨对RABV的致病性有重要影响的糖蛋白(Glycoprotein,G)在调节IFN-I通路方面扮演怎样的角色。【方法】将RABV弱毒株Hep-Flury的G基因替换成致病株CVS-11的G基因,拯救得到重组病毒HepG,分析Hep-Flury、CVS-11和HepG这3种毒株在体内和体外感染对IFN-I通路激活和调控的差别,比较它们在神经细胞中对抗IFN-I抗病毒作用的差异性。【结果】替换了CVS-11的G基因后,重组病毒HepG致病力增强,能够100%致死小鼠,在鼠脑中的增殖水平显著高于亲本株Hep-Flury。在感染鼠脑早期及体外神经细胞时,弱毒株Hep-Flury能够较快地激活IFN-I通路相关基因的表达,重组病毒HepG的激活能力介于HepFlury和CVS-11之间。利用Poly(I:C)激活神经细胞的IFN-I通路后,Hep-Flury的增殖被显著抑制,CVS-11和HepG的复制几乎不受影响,表现出一定的抵抗能力。【结论】RABV的G蛋白在调节和抵抗IFN-I通路方面发挥重要功能,为进一步探究RABV致病毒株的G蛋白如何协助病毒在中枢神经系统中逃逸IFN-I提供了线索和依据。

斜带石斑鱼IFN-γ基因的克隆与表达分析

IFN-γ在天然免疫和适应性免疫应答中均发挥着重要的作用。由于低等脊椎动物IFN-γ与哺乳动物IFN-γ相似性非常低,硬骨鱼类的IFN-γ近年来才得到鉴定。本研究报道了斜带石斑鱼(Epinephelus coioides)的IFN-γ基因,并对其表达进行了分析。斜带石斑鱼IFN-γcDNA全长为867 bp,编码200个氨基酸。其基因组全长为5 104 bp,由4个外显子、3个内含子组成。氨基酸序列比对显示斜带石斑鱼IFN-γ与高等脊椎动物IFN-γ的序列相似性较低,仅为32.5%～39%,与其他硬骨鱼类的IFN-γ相似性为38.0%～68.5%。序列分析结果显示,斜带石斑鱼IFN-γ分子C末端中存在IFN-γ的特征序列以及核定位基序。二级结构分析结果显示斜带石斑鱼IFN-γ序列中包含6个α螺旋结构,其排列与高等脊椎动物的IFN-γ类似。应用荧光定量PCR检测了IFN-γ基因在Poly I:C诱导后的表达变化。发现在肾、脾、鳃、头肾、皮肤和胸腺组织中,Poly I:C能显著诱导IFN-γ的表达,在胸腺中上调倍数最高,其次为头肾、脾、肾、皮肤和鳃,而在脑和心脏组织中没有显著变化。据此推测,IFN-γ在斜带石斑鱼抵抗病毒感染的过程中起有十分重要的作用。