Translational insensitivity to potent activation of PKR by HCV IRES RNA

Translation of hepatitis C virus (HCV) is initiated at an internal ribosome entry site (IRES) located at the 5′end of its RNA genome. The HCV IRES is highly structured and greater than 50% of its nucleotides form based-paired helices. We report here that the HCV IRES is an activator of PKR, an interferon-induced enzyme that participates in host cell defense against viral infection. Binding of HCV IRES RNA to PKR leads to a greatly increased (20-fold) rate and level (4.5-fold) of PKR autophosphorylation compared to previously studied dsRNA activators. We have mapped the domains in the IRES required for PKR activation to domains III–IV and demonstrate that the N-terminal double-stranded RNA binding domains of PKR bind to the IRES in a similar manner to other RNA activators. Addition of HCV IRES RNA inhibits cap-dependent translation in lysates via phosphorylation of PKR and eIF2α. However, HCV IRES-mediated translation is not inhibited by the phosphorylation of PKR and eIF2α. The results presented here suggest that hydrolysis of GTP by eIF2 is not an essential step in IRES-mediated translation. Thus, HCV can use structured RNAs to its advantage in translation, while avoiding the deleterious effects of PKR activation.     

The antiviral effect of jiadifenoic acids C against coxsackievirus B3

Coxsackievirus B type 3 (CVB3) is one of the major causative pathogens associated with viral meningitis and myocarditis, which are widespread in the human population and especially prevalent in neonates and children. These infections can result in dilated cardiomyopathy (DCM) and other severe clinical complications. There are no vaccines or drugs approved for the prevention or therapy of CVB3-induced diseases. During screening for anti-CVB3 candidates in our previous studies, we found that jiadifenoic acids C exhibited strong antiviral activities against CVB3 as well as other strains of Coxsackie B viruses (CVBs). The present studies were carried out to evaluate the antiviral activities of jiadifenoic acids C. Results showed that jiadifenoic acids C could reduce CVB3 RNA and proteins synthesis in a dose-dependent manner. Jiadifenoic acids C also had a similar antiviral effect on the pleconaril-resistant variant of CVB3. We further examined the impact of jiadifenoic acids C on the synthesis of viral structural and non-structural proteins, finding that jiadifenoic acids C could reduce VP1 and 3D protein production. A time-course study with Vero cells showed that jiadifenoic acids C displayed significant antiviral activities at 0–6 h after CVB3 inoculation, indicating that jiadifenoic acids C functioned at an early step of CVB3 replication. However, jiadifenoic acids C had no prophylactic effect against CVB3. Taken together, we show that jiadifenoic acids C exhibit strong antiviral activities against all strains of CVB, including the pleconaril-resistant variant. Our study could provide a significant lead for anti-CVB3 drug development.KEY WORDS: CVB3, Jiadifenoic acids C, Antiviral activityAbbreviations: CAR, coxsackievirus and adenovirus receptor; CPE, cytopathic effect; CVB3, coxsackievirus B type 3; CVBs, coxsackie B viruses; DAF, decay accelerating factor; DCM, dilated cardiomyopathy; IC₅₀, 50% inhibitory concentration; IRES, internal ribosomal entry site; MOI, multiplicity of infection; NTR, non-translated region; RBV, ribavirin; RdRp, RNA-dependent RNA polymerase; SI, selectivity index; Vero, African green monkey kidney cells     

Phyllaemblicin B inhibits Coxsackie virus B3 induced apoptosis and myocarditis

Coxsackie virus B3 (CVB3) is believed to be a major contributor to viral myocarditis since virus-associated apoptosis plays a role in the pathogenesis of experimental myocarditis. In this study, we investigated the in vitro and in vivo antiviral activities of Phyllaemblicin B, the main ellagitannin compound isolated from Phyllanthus emblica, a Chinese herb medicine, against CVB3. Herein we report that Phyllaemblicin B inhibited CVB3-mediated cytopathic effects on HeLa cells with an IC₅₀ value of 7.75 ± 0.15 μg/mL. In an in vivo assay, treatment with 12 mg kg⁻¹ d⁻¹ Phyllaemblicin B reduced cardiac CVB3 titers, decreased the activities of LDH and CK in murine serum, and alleviated pathological damages of cardiac muscle in myocarditic mice. Moreover, Phyllaemblicin B clearly inhibited CVB3-associated apoptosis effects both in vitro and in vivo. These results show that Phyllaemblicin B exerts significant antiviral activities against CVB3. Therefore, Phyllaemblicin B may represent a potential therapeutic agent for viral myocarditis.     

Effect of prophylactically applied CpG ODN on the development of myocarditis in mice infected with Coxsackievirus B3

Coxsackievirus B3 was one of the major pathogens causing viral myocarditis. Toll-like receptor 9 activation contributed to the innate immune response in the process of CVB3-induced myocarditis. In order to find out how CpG oligodeoxynucleotide, known as a TLR-9 agonist, would affect the CVB3-induced myocarditis, we chose a C-type CpG oligodeoxynucleotide (YW002) injected to the mice one day before CVB3 challenge. On day 4 post CVB3 infection, 3 mice in each group were randomly sacrificed and their hearts were isolated to detect CVB3 replication. On day 10, the CVB3 neutralizing antibody and inflammatory change of the hearts were detected. The results indicated that the CVB3-induced myocarditis was aggravated with the declining body weight of mice, decreasing neutralizing antibody, and uncontrolling virus replication by injecting 20 μg YW002 per mouse. When adjusted the amount at 10 μg YW002 per mouse, there were no signs of aggravation in myocarditis. Plus, the mortality of the infected mice was reduced, the neutralizing antibody level was raised and the replication of virus was restrained. These results suggested that a proper amount of CpG oligodeoxynucleotide application could help to inhibit CVB3 infection.     

参麦注射液对感染柯萨奇B3病毒心肌细胞的影响

目的在细胞水平探讨参麦注射液（SMI）对实验性病毒性心肌炎的治疗作用。方法采用原代培养的SD大鼠心肌细胞感染柯萨奇B3病毒（CVB3）造成实验性病毒性心肌炎细胞模型;设立正常对照组、模型组、SMI高剂量（10g／L）组、SMI中剂量（5g／L）组及SMI低剂量（2．5g／L）组,观察心肌细胞感染CVB,后第3天和第5天的搏动频率、细胞病变、细胞超微结构、上清液中乳酸脱氢酶（LDH）的活性和CVB,滴度。结果感染CVB,后心肌细胞的搏动频率明显减慢;第5天模型组有半数细胞搏动停止,细胞病变明显,线粒体肿胀且形态不完整,内质网扩张,部分肌原纤维损坏,上清液中LDH的活性显著升高;SMI各剂量组心肌细胞均维持搏动,且高剂量组细胞病变程度、LDH活性和CVB,滴度均明显低于模型组,除部分肌原纤维损坏外,线粒体形态完整,内质网未见扩张。结论SMI对感染CVB,的培养心肌细胞搏动功能具有保护作用,并能降低心肌细胞上清液中CVB3滴度和减轻CVB,对心肌细胞的损伤。     

黄芪三萜皂苷对CVB3诱导病毒性心肌炎的保护作用研究

目的：研究黄芪三萜皂苷（Astragalus saponins,AST）对CVB3病毒诱导病毒性心肌炎的保护作用及机制。方法：利用CVB3病毒、原代心肌细胞及小鼠构建病毒性心肌炎模型并使用AST进行干预,在实验过程中记录小鼠的生存率和体质量变化,体外超声评价小鼠的心脏功能及检测心肌蛋白中LDH和CK-MB水平。心肌组织天狼星红染色评价纤维化水平及TUNNEL染色检测心肌凋亡情况。Western Blot检测心肌蛋白中Caspase-3和Fas表达情况以研究AST保护病毒性心肌炎的机制。结果：AST能够显著增加CVB3注射后的小鼠生存率、缓解CVB3诱导小鼠的体质量减轻。体外超声结果显示,AST能够显著改善CVB3诱导小鼠心脏的收缩功能障碍。CBV3诱导组小鼠心肌蛋白中LDH和CM-KB水平较正常小鼠显著增加,而AST对此有显著的抑制作用。心肌组织病理染色结果显示,AST对CVB3诱导的心肌扩张和纤维化具有显著的保护作用。CVB3诱导组小鼠心肌组织的凋亡水平显著高于正常小鼠,而AST对此有显著的抑制作用。在CVB3感染的心肌组织中,Caspase-3和Fas表达水平显著的升高,而AST能够显著的抑制CVB3诱导的二者在心肌组织中的表达。结论：AST通过提高小鼠的生存率、抑制心肌扩张、心肌组织纤维化和心肌细胞凋亡对CVB3诱导的病毒性心肌炎具有显著的保护作用,这种作用可能与抑制CVB3诱导的Caspase-3和Fas在心肌组织中表达有关。     

Viral manipulation of cell death

Elucidation of the mechanisms behind cell death has brought with it an appreciation for viral strategies that target these pathways as a means to promote viral propagation while avoiding or slowing the host immune response. Several redundant anti-viral pathways have evolved in eukaryotic cells that are designed to minimize the damage due to viral infection while quickly clearing the invading pathogen. Cell death is a commonly employed immune defense against viral infection, and many viruses potently induce or suppress cell death during infection. The past decade has seen an incredible increase in our understanding of how cell death assists in host immune response, as well as how viruses have evolved to hijack or disengage these systems. By targeting components of host cell death pathways, viruses have developed the ability to control host survival and death, ensuring efficient propagation while inactivating or avoiding the immune system consequences of infection. This review focuses on the most recent and important advances in our understanding of how a wide range of viruses manipulate the survival and death of their hosts.     

Selenium and viral virulence

A mouse model of coxsackievirus-induced myocarditis is being used to investigate nutritional determinants of viral virulence. This approach was suggested by research carried out in China which showed that mice fed diets composed of low selenium ingredients from a Keshan disease area suffered more extensive heart damage when infected with a coxsackie B4 virus than infected mice fed the same diet but supplemented with selenium by esophageal intubation. Selenium deficiency in our mice increased the virulence of an already virulent strain of coxsackievirus B3 (CVB3/20) and also allowed conversion of a non-virulent strain (CVB3/0) to virulence. Such conversion of CVB3/0 was accompanied by a change in the viral genome to more closely match that of the virulent virus, CVB3/20. As far as the authors are aware, this is the first report of host nutrition influencing the genetic make-up of an invading pathogen. Nutritionists may need to consider this mechanism of increased viral virulence in order to gain a better understanding of diet/infection relationships.     

Picornavirus IRES: structure function relationship

Picornavirus infections have been a challenging problem in human health. Genome organisation of picornavirus is unique in having a long, heavily-structured, multifunctional 5'untranslated region, preceding a single open reading frame from which all viral proteins are produced. Within the 5'leader, an internal region termed ribosome entry site (IRES) regulates viral protein synthesis in a 5'-independent manner. The IRES element itself is a distinctive feature of the picornavirus mRNAs, allowing efficient viral protein synthesis in infected cells in spite of a severe modification of translation initiation factors induced by viral proteases that lead to a fast inhibition of cellular protein synthesis. Picornavirus IRES elements are strongly structured, bearing several motifs, phylogenetically conserved, which are essential for IRES activity. Together with RNA structure, RNA-binding proteins play an essential role in the activity of the IRES element, having a profound effect on viral pathogenesis. Recent data on the involvement of these conserved motifs in RNA structure and protein recognition is discussed in detail. Understanding the interplay between these two components of IRES function is crucial to develop viral strategies aimed to use the viral RNA as the target of antiviral approaches.     

Cardiomyocyte-specific deletion of Senp2 contributes to CVB3 viral replication and inflammation

Viral myocarditis (VMC) is characterized by cardiac inflammation and excessive inflammatory responses after viral infection. SENP2, a deSUMO-specific protease, has been reported to regulate antiviral innate immunity. This study aimed to investigate whether SENP2 affects CVB3-induced VMC. We generated a CVB3-induced VMC mouse model in 6-week-old cardiomyocyte-specific Senp2 knockout mice. The mice were sacrificed at days 0, 2, 4 and 6 after CVB3 infection. The survival rate, body weight, myocardial histopathological changes, viral load, cytokine levels and antiviral gene expression in cardiac tissues of both groups were investigated. Our study indicated that the expression of Senp2 in primary cardiomyocytes was upregulated by CVB3 infection. Moreover, deletion of Senp2 in the heart exacerbated CVB3 infection-induced myocarditis, facilitated CVB3 viral replication and downregulated the expression of antiviral proteins. In conclusion, our findings suggest a protective role for SENP2 in CVB3-induced VMC.     

The human fatty acid synthase: a new therapeutic target for coxsackievirus B3-induced diseases?

Coxsackievirus is linked to a large variety of severe human and animal diseases such as myocarditis. The interplay between host factors and virus components is crucial for the fate of the infected cells. However, host proteins which may play a role in coxsackievirus-induced diseases are ill-defined. Two-dimensional gel electrophoresis of protein extracts obtained from coxsackievirus B3 (CVB3)-infected and uninfected HeLa or HepG2 cells combined with spot analysis revealed several proteins which are exclusively up-regulated in infected cells. One of these proteins was identified as the fatty acid synthase (FAS). By using cerulenin and C75, two known inhibitors of FAS we were able to significantly block CVB3 replication. FAS appears to be directly involved in CVB3-caused pathology and is therefore suitable as a therapeutic target in CVB3-induced diseases.     

肉桂油抗柯萨奇病毒B3的血清药理学研究

目的 利用血清药理学方法 探讨肉桂油抗柯萨奇病毒B3(CVB3)的作用机制. 方法 制备SD大鼠乳鼠心肌炎细胞模型,72 h后,加入肉桂油静脉给药所得的大鼠含药血清至感染细胞模型,同时设立模型组与空白对照组,测定血清中不同时间点桂皮醛与肉桂酸的含量,并采用实时定量聚合酶链反应(PCR)法测定各组CVB3mRNA的相对含量,噻唑蓝(MTT)比色法测定各组心肌细胞存活率. 采用SPSS统计学软件对其进行单因素相关性分析. 结果肉桂油含药血清对心肌细胞存活率和CVB3mRNA的相对含量的影响与肉桂酸的浓度相关(P<0.05或P<0.01),而与桂皮醛的浓度无显著相关. 结论 肉桂油对病毒性心肌炎具有抗病毒活性,肉桂酸是肉桂油抗病毒的活性成分.     

Short peptide nucleic acids (PNA) inhibit hepatitis C virus internal ribosome entry site (IRES) dependent translation in vitro

The internal ribosome entry site (IRES) of hepatitis C virus (HCV) which governs the initiation of protein synthesis from viral RNA represents an ideal target for antisense approaches. Using an original bicistronic plasmid, we first established that sequence and translational activity of HCV IRESs cloned from six patients, whether responders or not to combination therapy, were conserved. We then tested the hypothesis that antisense molecules, i.e. short peptide nucleic acids (PNA), could inhibit HCV translation by binding to the highly conserved IIId or IV loop regions of the IRES. Five 6–10 mer PNAs were designed. They strongly inhibit HCV IRES-driven translation in a rabbit reticulocyte lysate assay. This inhibition was highly specific since corresponding PNAs with only one mismatch were inactive. Short phosphorothioate oligonucleotides of same sequence were unable to inhibit HCV translation. PNA molecule was shown to have anti-HCV activity in Huh-7.5 cells when electroporated with a full-length HCV genome construct. Using oligonucleotide as carrier, PNA was also transfected in HCV replicon-harboring cells and in JFH1 infected Huh-7.5 cells.     

The comparison of α-bromo-4-chlorocinnamaldehyde and cinnamaldehyde on coxsackie virus B3-induced myocarditis and their mechanisms

Early experiments showed cinnamaldehyde had obvious therapeutic effect on viral myocarditis, but cinnamaldehyde was unstable in vivo. To overcome this limitation, we used cinnamaldehyde as a lead compound to synthesize α-bromo-4-chlorocinnamaldehyde (BCC). In the present study, we compared the therapeutic effects of BCC with cinnamaldehyde on coxsackie virus B3 (CVB3)-induced viral myocarditis (VMC), as well as investigated the possible mechanism. The antiviral and cytotoxic effects in vitro were evaluated on HeLa cells infected by CVB3 and rat cardiomyocytes respectively. Our results showed that IC50 were 0.78±0.13 μM and 48.16±5.79 μM in BCC and cinnamaldehyde-treated cells. 50% toxic concentration (TC) in BCC-treated cells was 22-fold higher than in the cinnamaldehyde group. In vivo BALB/c mice were infected with CVB3 for establishing VMC models. The results demonstrated that BCC reduced the viral titers and cardiac pathological changes in a dose-dependent manner. Myocardial virus titers were significantly lower in the 50 mg/kg BCC-treated group than in cinnamaldehyde groups. In addition, BCC could significantly inhibit the replication of CVB3 mRNA and the secretion of inflammatory cytokines TNF-α, IL-β and IL-6 in CVB3-infected cardiomyocytes. We further observed that BCC suppressed CVB3-induced NF-κB activation, IκB-α degradation and phosphorylation in a concentration-dependent manner, and reduced Toll like receptor (TLR) 4 protein level in hearts. These results suggest that BCC had a promising therapeutic effect on VMC with a highly significant favorable effects and less toxicity than cinnamaldehyde. Furthermore, the effect of BCC on VMC might be through inhibition of inflammatory signaling.     

Short peptide nucleic acids (PNA) inhibit hepatitis C virus internal ribosome entry site (IRES) dependent translation in vitro

The internal ribosome entry site (IRES) of hepatitis C virus (HCV) which governs the initiation of protein synthesis from viral RNA represents an ideal target for antisense approaches. Using an original bicistronic plasmid, we first established that sequence and translational activity of HCV IRESs cloned from six patients, whether responders or not to combination therapy, were conserved. We then tested the hypothesis that antisense molecules, i.e. short peptide nucleic acids (PNA), could inhibit HCV translation by binding to the highly conserved IIId or IV loop regions of the IRES. Five 6–10 mer PNAs were designed. They strongly inhibit HCV IRES-driven translation in a rabbit reticulocyte lysate assay. This inhibition was highly specific since corresponding PNAs with only one mismatch were inactive. Short phosphorothioate oligonucleotides of same sequence were unable to inhibit HCV translation. PNA molecule was shown to have anti-HCV activity in Huh-7.5 cells when electroporated with a full-length HCV genome construct. Using oligonucleotide as carrier, PNA was also transfected in HCV replicon-harboring cells and in JFH1 infected Huh-7.5 cells.     

氧化苦参碱对病毒性心肌炎小鼠心肌细胞凋亡及相关因子的影响

目的 探讨氧化苦参碱(oxymatrine,OMT)对病毒性心肌炎小鼠心肌细胞凋亡及其凋亡相关因子蛋白表达的影响。方法 42只BALB/c小鼠随机分为正常对照组(NC)、病毒性心肌炎模型组(VM)、OMT高剂量组(OMT-H,25?mg·kg^-1·d^-1)、OMT中剂量组(OMT-M,12.5 mg·kg^-1·d^-1)、OMT低剂量组(OMT-L,6.25 mg·kg^-1·d^-1)、OMT极低剂量组(OMT-EL,3.125 mg·kg^-1·d^-1)、利巴韦林对照组(RB,100 mg·kg^-1·d^-1)。病毒性心肌炎小鼠由柯萨奇病毒B3型腹腔注射感染所致,各治疗组从末次给予病毒24 h后开始,腹腔注射,每日1次。于治疗第12天,每组处死小鼠6只,留取心肌标本。TUNEL法检测心肌细胞凋亡情况,免疫印迹法和免疫组织化学法检测Bcl-2和Bax蛋白的表达情况。结果 OMT治疗显著降低了病毒性心肌炎小鼠凋亡心肌细胞的数量,与病毒性心肌炎模型组比较,OMT-L组效果最佳(P<0.01)。与病毒性心肌炎模型组小鼠比较,OMT治疗组的小鼠心肌组织中Bax蛋白表达降低,而Bcl-2蛋白表达没有明显改变。结论 氧化苦参碱可减少病毒性心肌炎小鼠心肌细胞的凋亡,该作用与下调Bax蛋白表达有关。     

An engineered inhibitor RNA that efficiently interferes with hepatitis C virus translation and replication

Hepatitis C virus (HCV) translation is mediated by a highly conserved internal ribosome entry site (IRES), mainly located at the 5'untranslatable region (5'UTR) of the viral genome. Viral protein synthesis clearly differs from that used by most cellular mRNAs, rendering the IRES an attractive target for novel antiviral compounds. The engineering of RNA compounds is an effective strategy for targeting conserved functional regions in viral RNA genomes. The present work analyses the anti-HCV potential of HH363-24, an in vitro selected molecule composed of a catalytic RNA cleaving domain with an extension at the 3' end that acts as aptamer for the viral 5'UTR. The engineered HH363-24 efficiently cleaved the HCV genome and bound to the essential IIId domain of the IRES region. This action interfered with the proper assembly of the translationally active ribosomal particles 48S and 80S, likely leading to effective inhibition of the IRES function in a hepatic cell line. HH363-24 also efficiently reduced HCV RNA levels up to 70% in a subgenomic replicon system. These findings provide new insights into the development of potential therapeutic strategies based on RNA molecules targeting genomic RNA structural domains and highlight the feasibility of generating novel engineered RNAs as potent antiviral agents.     

Treg responses are associated with PM2.5-induced exacerbation of viral myocarditis

Abstract

The adverse cardiovascular events induced by ambient fine particles (PM_2.5) are paid more attention in the world. The current study was conducted to explore the mechanisms of T regulatory cells (Treg) responses in PM_2.5-induced exacerbation of viral myocarditis. The male BALB/c mice were administered an intratracheal (i.t.) instillation of 10?mg/kg b.w. PM_2.5 suspension. Twenty-four hours later, the mice were injected intraperitoneally (i.p.) with 100?μl of coxsackievirus B3 (CVB3) diluted in Eagle's minimal essential medium (EMEM). Seven days after the treatment, serum, splenetic, and cardiac tissues were examined. The results showed that pre-exposure to PM_2.5 aggravated the cardiac inflammation in the CVB3-infected mice along with an increase of Treg cells in the spleen. The mRNA expressions of interleukin-6 (IL-6), TNF-α, transforming growth factor-β (TGF-β), and Foxp3 were up-regulated in the PM_2.5-pretreated mice than that in the CVB3-treated mice. Similar results were found in the sera. In addition, compared with the CVB3-treated mice, the cardiac protein expression of TGF-β increased in the PM_2.5-pretreated mice. These results demonstrated that preexposure to PM_2.5 exacerbated virus-induced myocarditis possibly through the depression of the immune response and increase of inflammation in myocardium through the Treg responses.     

蛋白酶体抑制剂MG-132对柯萨奇B3病毒性心肌炎小鼠的作用研究

目的：研究泛素蛋白酶体抑制剂MG-132对柯萨奇B3（CVB3）病毒性心肌炎小鼠的作用,探讨泛素蛋白酶体系统在病毒性心肌炎发病学中的作用机制。方法：随机将80只雄性BALB／C小鼠分为4组（,2—20）：正常对照组、心肌炎组、心肌炎＋处理组、正常＋处理组。腹腔接种CVB3诱发急性心肌炎,次日腹腔注射MG-132,0．75mg／kg;连续给药7d,对照组腹腔注射PBS。第8天小鼠取材,观察心脏病理变化,测定心肌CVB3病毒复制及血清肌钙蛋白、脑钠肽水平。结果：MG-132显著减轻心肌炎小鼠心脏病理损伤,显著降低心脏重量／身体重量比值,MG-132干预后第8天小鼠血清肌钙蛋白、脑钠肽水平显著降低,同时荧光定量PCR显示CVB3mR—NA复制水平显著降低。结论：MG-132通过抑制CVB3病毒复制,显著减轻心肌炎小鼠心脏病理损伤,起到保护心肌作用。     

Polybrominated diphenyl ether exposure suppresses cytokines important in the defence to coxsackievirus B3 infection in mice

Environmental pollutants can adversely affect the immune system. The host defence during infection depends on cytokine signalling and proper function of immune cells. However, no studies have addressed how polybrominated diphenyl ethers (PBDEs) affect cytokine responses. We investigated the combined effects in Balb/c mice of human coxsackievirus B3 (CVB3) infection and exposure to PBDEs (BDE-99 or Bromkal mixture) on 21 serum cytokines. The mice were infected (i.p.) on day 0, orally treated with BDE-99 or Bromkal on day 1 (20 mg/kg bw) and put to death on day 3. CVB3 was quantitatively measured in the liver and pancreas by RT-PCR. The Luminex 200 multi-analyte system was used for cytokine analysis. High numbers of viral copies were found in the liver and pancreas. Infection increased TNF-α, IL-6, MCP-1, IL-12p40, KC and RANTES levels. Notably, PBDE-exposure resulted in a marked decrease, or even lack, of IL-13, MIP-1β, RANTES, IFN-γ and KC levels in non-infected mice. However, the effects of PBDE-exposure on cytokines did not affect viral replication during early CVB3 infection. In conclusion, PBDEs causes a selective block in immune signalling pathways but the consequences of this need to be further studied in different host resistance models of infection.