Tick-borne encephalitis virus (TBEV), of the genus Flavivirus, is a causative agent of severe encephalitis in regions of endemicity of northern Asia and central and northern Europe. Interferon-induced transmembrane proteins (IFITMs) are restriction factors that inhibit the replication cycles of numerous viruses, including flaviviruses such as West Nile virus, dengue virus, and Zika virus. Here, we demonstrate the role of IFITM1, IFITM2, and IFITM3 in the inhibition of TBEV infection and in protection against virus-induced cell death. We show that the most significant role is that of IFITM3, including the dissection of its functional motifs by mutagenesis. Furthermore, through the use of CRISPR-Cas9-generated IFITM1/3-knockout monoclonal cell lines, we confirm the role and additive action of endogenous IFITMs in TBEV suppression. However, the results of coculture assays suggest that TBEV might partially escape interferon- and IFITM-mediated suppression during high-density coculture infection when the virus enters naive cells directly from infected donor cells. Thus, cell-to-cell spread may constitute a strategy for virus escape from innate host defenses. IMPORTANCE TBEV infection may result in encephalitis, chronic illness, or death. TBEV is endemic in northern Asia and Europe; however, due to climate change, new centers of endemicity have arisen. Although effective TBEV vaccines have been approved, vaccination coverage is low, and due to the lack of specific therapeutics, infected individuals depend on their immune responses to control the infection. IFITM proteins are components of the innate antiviral defenses that suppress cell entry of many viral pathogens. However, no studies on the role of IFITM proteins in TBEV infection have been published thus far. Understanding antiviral innate immune responses is crucial for the future development of antiviral strategies. Here, we show the important role of IFITM proteins in the inhibition of TBEV infection and virus-mediated cell death. However, our data suggest that TBEV cell-to-cell spread may be less prone to both interferon- and IFITM-mediated suppression, potentially facilitating escape from IFITM-mediated immunity.

• MeSH
• buněčné linie MeSH
• cytopatogenní efekt virový MeSH
• exprese genu MeSH
• genový knockdown MeSH
• interakce hostitele a patogenu * genetika   imunologie   MeSH
• interakční proteinové domény a motivy MeSH
• interferony metabolismus   MeSH
• klíšťová encefalitida genetika   imunologie   metabolismus   virologie   MeSH
• lidé MeSH
• membránové proteiny chemie   genetika   metabolismus   MeSH
• multigenová rodina MeSH
• náchylnost k nemoci MeSH
• odolnost vůči nemocem genetika   imunologie   MeSH
• replikace viru MeSH
• sekvence aminokyselin MeSH
• vazba proteinů MeSH
• viry klíšťové encefalitidy fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The flavivirus, tick-borne encephalitis virus (TBEV) is transmitted by Ixodes spp. ticks and may cause severe and potentially lethal neurological tick-borne encephalitis (TBE) in humans. Studying TBEV requires the use of secondary methodologies to detect the virus in infected cells. To overcome this problem, we rationally designed and constructed a recombinant reporter TBEV that stably expressed the mCherry reporter protein. The resulting TBEV reporter virus (named mCherry-TBEV) and wild-type parental TBEV exhibited similar growth kinetics in cultured cells; however, the mCherry-TBEV virus produced smaller plaques. The magnitude of mCherry expression correlated well with progeny virus production but remained stable over <4 passages in cell culture. Using well-characterized antiviral compounds known to inhibit TBEV, 2'-C-methyladenosine and 2'-deoxy-2'-β-hydroxy-4'-azidocytidine (RO-9187), we demonstrated that mCherry-TBEV is suitable for high-throughput screening of antiviral drugs. Serum samples from a TBEV-vaccinated human and a TBEV-infected dog were used to evaluate the mCherry-based neutralization test. Collectively, recombinant mCherry-TBEV reporter virus described here provides a powerful tool to facilitate the identification of potential antiviral agents, and to measure levels of neutralizing antibodies in human and animal sera.

• MeSH
• antivirové látky izolace a purifikace   MeSH
• buněčné linie MeSH
• klíšťová encefalitida imunologie   virologie   MeSH
• křečci praví MeSH
• ledviny cytologie   MeSH
• lidé MeSH
• luminescentní proteiny genetika   MeSH
• neutralizační testy * MeSH
• neutralizující protilátky krev   MeSH
• protilátky virové krev   MeSH
• rychlé screeningové testy metody   MeSH
• viry klíšťové encefalitidy genetika   růst a vývoj   MeSH
• zvířata MeSH
• Check Tag
• křečci praví MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Tick-borne encephalitis virus (TBEV) is an emerging human pathogen that causes potentially fatal disease with no specific treatment. Mouse monoclonal antibodies are protective against TBEV, but little is known about the human antibody response to infection. Here, we report on the human neutralizing antibody response to TBEV in a cohort of infected and vaccinated individuals. Expanded clones of memory B cells expressed closely related anti-envelope domain III (EDIII) antibodies in both groups of volunteers. However, the most potent neutralizing antibodies, with IC50s below 1 ng/ml, were found only in individuals who recovered from natural infection. These antibodies also neutralized other tick-borne flaviviruses, including Langat, louping ill, Omsk hemorrhagic fever, Kyasanur forest disease, and Powassan viruses. Structural analysis revealed a conserved epitope near the lateral ridge of EDIII adjoining the EDI-EDIII hinge region. Prophylactic or early therapeutic antibody administration was effective at low doses in mice that were lethally infected with TBEV.

• MeSH
• analýza přežití MeSH
• epitopy imunologie   MeSH
• imunoglobulin G aplikace a dávkování   imunologie   MeSH
• klíšťová encefalitida imunologie   prevence a kontrola   virologie   MeSH
• kohortové studie MeSH
• kultivované buňky MeSH
• lidé MeSH
• monoklonální protilátky aplikace a dávkování   genetika   imunologie   MeSH
• myši inbrední BALB C MeSH
• neutralizující protilátky aplikace a dávkování   genetika   imunologie   MeSH
• proteiny virového obalu genetika   imunologie   MeSH
• protilátky virové aplikace a dávkování   genetika   imunologie   MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin MeSH
• viry klíšťové encefalitidy účinky léků   imunologie   fyziologie   MeSH
• zkřížené reakce imunologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

BACKGROUND: Tick-borne encephalitis (TBE) is a severe neuropathological disorder caused by tick-borne encephalitis virus (TBEV). Brain TBEV infection is characterized by extensive pathological neuroinflammation. The mechanism by which TBEV causes CNS destruction remains unclear, but growing evidence suggests that it involves both direct neuronal damage by the virus infection and indirect damage caused by the immune response. Here, we aimed to examine the TBEV-infection-induced innate immune response in mice and in human neural cells. We also compared cytokine/chemokine communication between naïve and infected neuronal cells and astrocytes. METHODS: We used a multiplexed Luminex system to measure multiple cytokines/chemokines and growth factors in mouse serum samples and brain tissue, and in human neuroblastoma cells (SK-N-SH) and primary cortical astrocytes (HBCA), which were infected with the highly pathogenic TBEV strain Hypr. We also investigated changes in cytokine/chemokine production in naïve HBCA cells treated with virus-free supernatants from TBEV-infected SK-N-SH cells and in naïve SK-N-SH cells treated with virus-free supernatants from TBEV-infected HBCA cells. Additionally, a plaque assay was performed to assess how cytokine/chemokine treatment influenced viral growth following TBEV infection. RESULTS: TBEV-infected mice exhibited time-dependent increases in serum and brain tissue concentrations of multiple cytokines/chemokines (mainly CXCL10/IP-10, and also CXCL1, G-CSF, IL-6, and others). TBEV-infected SK-N-SH cells exhibited increased production of IL-8 and RANTES and downregulated MCP-1 and HGF. TBEV infection of HBCA cells activated production of a broad spectrum of pro-inflammatory cytokines, chemokines, and growth factors (mainly IL-6, IL-8, CXCL10, RANTES, and G-CSF) and downregulated the expression of VEGF. Treatment of SK-N-SH with supernatants from infected HBCA induced expression of a variety of chemokines and pro-inflammatory cytokines, reduced SK-N-SH mortality after TBEV infection, and decreased virus growth in these cells. Treatment of HBCA with supernatants from infected SK-N-SH had little effect on cytokine/chemokine/growth factor expression but reduced TBEV growth in these cells after infection. CONCLUSIONS: Our results indicated that both neurons and astrocytes are potential sources of pro-inflammatory cytokines in TBEV-infected brain tissue. Infected/activated astrocytes produce cytokines/chemokines that stimulate the innate neuronal immune response, limiting virus replication, and increasing survival of infected neurons.

• MeSH
• cytokiny imunologie   metabolismus   MeSH
• klíšťová encefalitida imunologie   metabolismus   MeSH
• lidé MeSH
• mozek imunologie   metabolismus   patologie   MeSH
• myši MeSH
• neurony imunologie   metabolismus   virologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• ELISA MeSH
• klíšťová encefalitida * imunologie   krev   MeSH
• laboratoře MeSH
• lidé MeSH
• řízení kvality MeSH
• sérologické testy * metody   MeSH
• statistika jako téma MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• hodnotící studie MeSH

A new simple electrochemical immunosensor approach for the determination of antibodies to tick-borne encephalitis virus (TBEV) in immunological products was developed and tested. The assay is performed by detecting the silver reduction signal in the bioconjugates with antibodies (Ab@AgNP). Here, signal is read by cathodic linear sweep voltammetry (CLSV) through the detection of silver chloride reduction on a gold-carbon composite electrode (GCCE). Covalent immobilization of the antigen on the electrode surface was performed after thiolation and glutarization of the GCCE. Specific attention has been paid to the selection of conditions for stabilizing both the silver nanoparticles and their Ab@AgNP. A simple flocculation test with NaCl was used to select the concentration of antibodies, and the additional stabilizer bovine serum albumin (BSA) was used for Ab@AgNP preparation. The antibodies to TBEV were quantified in the range from 50 IU·mL-1 to 1600 IU·mL-1, with a detection limit of 50 IU·mL-1. The coefficient of determination (r2) is 0.989. The electrochemical immunosensor was successfully applied to check the quality of immunological products containing IgG antibodies to TBEV. The present work paves the path for a novel method for monitoring TBEV in biological fluids.

• MeSH
• elektrochemické techniky metody   MeSH
• elektrody MeSH
• imunoanalýza metody   MeSH
• klíšťová encefalitida diagnóza   imunologie   MeSH
• kovové nanočástice chemie   ultrastruktura   MeSH
• protilátky virové imunologie   MeSH
• sérový albumin hovězí MeSH
• skot MeSH
• spektrofotometrie ultrafialová MeSH
• stříbro chemie   MeSH
• velikost částic MeSH
• viry klíšťové encefalitidy imunologie   MeSH
• zvířata MeSH
• Check Tag
• skot MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Tick-borne encephalitis (TBE) is an illness caused by tick-borne encephalitis virus (TBEV) infection which is often limited to a febrile illness, but may lead to very aggressive downstream neurological manifestations. The disease is prevalent in forested areas of Europe and northeastern Asia, and is typically caused by infection involving one of three TBEV subtypes, namely the European (TBEV-Eu), the Siberian (TBEV-Sib), or the Far Eastern (TBEV-FE) subtypes. In addition to the three main TBEV subtypes, two other subtypes; i.e., the Baikalian (TBEV-Bkl) and the Himalayan subtype (TBEV-Him), have been described recently. In Europe, TBEV-Eu infection usually results in only mild TBE associated with a mortality rate of <2%. TBEV-Sib infection also results in a generally mild TBE associated with a non-paralytic febrile form of encephalitis, although there is a tendency towards persistent TBE caused by chronic viral infection. TBE-FE infection is considered to induce the most severe forms of TBE. Importantly though, viral subtype is not the sole determinant of TBE severity; both mild and severe cases of TBE are in fact associated with infection by any of the subtypes. In keeping with this observation, the overall TBE mortality rate in Russia is ∼2%, in spite of the fact that TBEV-Sib and TBEV-FE subtypes appear to be inducers of more severe TBE than TBEV-Eu. On the other hand, TBEV-Sib and TBEV-FE subtype infections in Russia are associated with essentially unique forms of TBE rarely seen elsewhere if at all, such as the hemorrhagic and chronic (progressive) forms of the disease. For post-exposure prophylaxis and TBE treatment in Russia and Kazakhstan, a specific anti-TBEV immunoglobulin is currently used with well-documented efficacy, but the use of specific TBEV immunoglobulins has been discontinued in Europe due to concerns regarding antibody-enhanced disease in naïve individuals. Therefore, new treatments are essential. This review summarizes available data on the pathogenesis and clinical features of TBE, plus different vaccine preparations available in Europe and Russia. In addition, new treatment possibilities, including small molecule drugs and experimental immunotherapies are reviewed. The authors caution that their descriptions of approved or experimental therapies should not be considered to be recommendations for patient care.

• MeSH
• antivirové látky terapeutické užití   MeSH
• fylogeneze MeSH
• klíšťata virologie   MeSH
• klíšťová encefalitida farmakoterapie   imunologie   prevence a kontrola   MeSH
• lidé MeSH
• myši MeSH
• virové vakcíny imunologie   MeSH
• viry klíšťové encefalitidy imunologie   patogenita   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Geografické názvy
• Evropa MeSH
• Rusko MeSH

OBJECTIVE: The aim of our study is to evaluate immune response after receiving the primary vaccination against tick-borne encephalitis (TBE), and to establish a link between seropositivity and selected factors in soldiers. METHODS: Blood samples, questionnaires and vaccination records were obtained. TBE antibodies were detected using both ELISA and a neutralization test (NT). We used logistic regression for statistical analysis. RESULTS: Overall, seropositivity (presence of IgG) was detected in 88% of participants. The proportion of seropositive subjects in relation to the number of doses of vaccine was 69% (2 doses) and 91% (3 doses). A statistically significant relationship was found between seropositivity and the number of vaccine doses. No statistical significance was identified in relation to age and sex. There was no statistical significance of seropositivity, depending on the time of the last dose of the vaccine. CONCLUSIONS: TBE immunisation should be targeted at individuals in the most affected locations and those at highest risk of exposure according to lifestyle and occupation.

• MeSH
• dospělí MeSH
• ELISA MeSH
• imunoglobulin G krev   MeSH
• klíšťová encefalitida krev   imunologie   prevence a kontrola   MeSH
• lidé středního věku MeSH
• lidé MeSH
• neutralizační testy MeSH
• ozbrojené síly statistika a číselné údaje   MeSH
• protilátky virové krev   MeSH
• vakcinace * MeSH
• virové vakcíny aplikace a dávkování   imunologie   MeSH
• viry klíšťové encefalitidy imunologie   izolace a purifikace   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

OBJECTIVE: The aim of this seroepidemiological study was to determine the current prevalence of antibodies against tick-borne encephalitis virus (TBEV) in the representative group of Slovak population with included potential risk factors for TBEV. METHODS: Representative group consisted of 428 persons (also with possible exposure to risk factors for tick bite or raw milk consumption). Serum samples were screened by commercial enzyme-linked immunosorbent assay (ELISA). The persons involved in the study completed questionnaires with general demographic, epidemiological and clinical data. During the analysis, we used linear regression to interpret the influence between selected variables. RESULTS: We detected 1.2% prevalence of positive IgG and 1.6% prevalence of positive IgM antibodies in all tested groups. Our results also confirmed that the following risk factors such as tourism, hunting, fishing, and consumption of raw milk are significantly associated with the prevalence of specific antibodies against TBEV. CONCLUSION: The results of seroprevalence obtained by this study confirm the possibility of infection with TBEV among respondents exposed to possible contact with ticks.

• MeSH
• dospělí MeSH
• ELISA MeSH
• imunoglobulin G krev   MeSH
• klíšťová encefalitida diagnóza   epidemiologie   imunologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• protilátky virové krev   MeSH
• průřezové studie MeSH
• rizikové faktory MeSH
• séroepidemiologické studie MeSH
• viry klíšťové encefalitidy genetika   imunologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Slovenská republika MeSH

Tick-borne encephalitis virus (TBEV) is a member of the genus Flavivirus. It can cause serious infections in humans that may result in encephalitis/meningoencephalitis. Although several studies have described the involvement of specific genes in the host response to TBEV infection in the central nervous system (CNS), the overall network remains poorly characterized. Therefore, we investigated the response of DAOY cells (human medulloblastoma cells derived from cerebellar neurons) to TBEV (Neudoerfl strain, Western subtype) infection to characterize differentially expressed genes by transcriptome analysis. Our results revealed a wide panel of interferon-stimulated genes (ISGs) and pro-inflammatory cytokines, including type III but not type I (or II) interferons (IFNs), which are activated upon TBEV infection, as well as a number of non-coding RNAs, including long non-coding RNAs. To obtain a broader view of the pathways responsible for eliciting an antiviral state in DAOY cells we examined the effect of type I and III IFNs and found that only type I IFN pre-treatment inhibited TBEV production. The cellular response to TBEV showed only partial overlap with gene expression changes induced by IFN-β treatment - suggesting a virus-specific signature - and we identified a group of ISGs that were highly up-regulated following IFN-β treatment. Moreover, a high rate of down-regulation was observed for a wide panel of pro-inflammatory cytokines upon IFN-β treatment. These data can serve as the basis for further studies of host-TBEV interactions and the identification of ISGs and/or lncRNAs with potent antiviral effects in cases of TBEV infection in human neuronal cells.

• MeSH
• aktivace transkripce MeSH
• cytokiny genetika   imunologie   MeSH
• interakce hostitele a patogenu MeSH
• interferony genetika   imunologie   MeSH
• klíšťová encefalitida genetika   imunologie   virologie   MeSH
• lidé MeSH
• neurony imunologie   virologie   MeSH
• viry klíšťové encefalitidy genetika   fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH