This thesis is focused on the role of host cytoskeleton, primarily microtubules and microfilaments, during tick-borne encephalitis virus infection in human neuroblastoma cell line SK-N-SH and tick cell line IRE/CTVM19. The importance of cytoskeletal integrity and dynamics to the viral replication cycle were examined using specific chemical inhibitors showing the virus utilizes studied structures in both cell lines. Immunofluorescence microscopy revealed structural changes in the actin cytoskeleton during late infection in SK-N-SH cells. Moreover, differences in expression of cytoskeleton-associated genes in both cell lines were compared. Several genes with up-regulated expression in SK-N-SH cells were identified during late infection.

The proposed thesis contributes to the basic knowledge in tick (Ixodes ricinus) and tick-borne pathogens (Borrelia burgdorferi sensu lato, tick-borne encephalitis virus) ecology in particular studying the spatial distribution, host associations and its causes and consequences in Central European habitats.

Ticks are important vectors of a wide variety of pathogens including protozoa, bacteria and viruses. Many of the viruses transmitted by ticks are of medical or veterinary importance including tick-borne encephalitis virus (TBEV) and Crimean- Congo hemorrhagic fever virus causing disease in humans, and African swine fever virus and Nairobi sheep disease virus affecting livestock. Although several studies have elucidated tick antimicrobial mechanisms including cellular immune responses such as nodulation, encapsulation and phagocytosis and humoral immune responses such as the JAK/STAT pathway, complement-like proteins, antimicrobial peptides, lectin like pattern-recognition molecules and lysozymes, very little is known about the innate immune response of ticks towards viral infection. This study therefore aimed to identify molecules that might be involved in the response of ticks to viral infection. The hypothesis was that TBEV infection leads to changes in the expression of immunity-related transcripts and proteins in Ixodes spp. tick cells and that at least some of these might be antiviral. Ixodes scapularis-derived cell lines IDE8 and ISE6 were chosen since I. scapularis is currently the only tick species with a sequenced genome and an Ixodes ricinus-derived cell line, IRE/CTVM19, was used because I. ricinus is the natural vector of TBEV. Basic parameters required to study the responses of tick cells to infection were determined, including levels of virus infection, kinetics of virus replication and production, formation of replication complexes and uptake of dsRNA or siRNA. The cell lines IDE8, ISE6 and IRE/CTVM19 were infected with either of two tick-borne flaviviruses, TBEV and Langat virus (LGTV), or with the mosquito-borne alphavirus Semliki Forest virus (SFV). Infection was characterised using techniques including plaque assay, luciferase assay, immunostaining and conventional, confocal and electron microscopy. Two time points for transcriptomics and proteomics analysis of TBEVinfected IDE8 and IRE/CTVM19 cells were selected: day 2 post-infection (p.i.) when virus production was increasing and day 6 p.i. when virus production was decreasing. RNA and protein were isolated from TBEV-infected and mock-infected tick cells at days 2 and 6 p.i. and RNA-Seq and mass spectrometric technologies were used to identify changes in, respectively, transcript and protein abundance. Differential expression of transcripts was determined using the data analysis package DESeq resulting in a total of 43 statistically significantly differentially expressed transcripts in IDE8 cells and 83 in IRE/CTVM19 cells, while differential protein representation using Χ2 test statistics with Bonferroni correction in IDEG6 software resulted in 76 differentially represented proteins in IDE8 cells and 129 in IRE/CTVM19 cells. These included transcripts and proteins which could affect stages of the virus infection, including virus entry, replication, maturation and protein trafficking, and also innate immune responses such as phagocytosis, RNA interference (RNAi), the complement system, the ubiquitin-proteasome pathway, cell stress and the endoplasmic reticulum (ER) stress response. After verification of sequencing data by qRT-PCR, the ability of several of the identified transcripts or proteins to affect virus infection was determined by knockdown experiments in IDE8 and IRE/CTVM19 cells using wild type LGTV, LGTV replicons or TBEV replicons. Knockdown of genes encoding proteins including the ER chaperone gp96 and the heat-shock protein HSP90 resulted in increased virus production in both cell lines, hinting at an antiviral role. In contrast, knockdown of calreticulin, another ER chaperone, resulted in a decrease in virus production in IRE/CTVM19 cells but not in IDE8 cells, implying a requirement for virus production. This functional genomics approach has identified possible novel genes/proteins involved in the interaction between flaviviruses and tick cells and also revealed that there might be antiviral innate immune pathways present in ticks additional to the exogenous RNAi pathway.

Erkinis encefalitas (EE) yra dažniausia ir sunkiausia virusinė nervų sistemos infekcija, neturinti specifinio priešvirusinio gydymo. Vienintelė efektyvi šios ligos profilaktikos priemonė yra vakcinacija. Nesant galimybių įvesti visuotinę vakcinaciją nuo EE mūsų šalyje, ypač svarbu nustatyti didžiausią šios ligos riziką turinčias gyventojų grupes, kurioms būtų teikiamas vakcinacijos prioritetas. Pagal tarptautines Laimo boreliozės (LB) diagnostikos ir gydymo gaires, klinikiniai sindromai ir jų trukmė yra svarbiausias šios ligos diagnostikos kriterijus. Serologiniai tyrimai vaidina tiktai pagalbinį vaidmenį patvirtinant diagnozę. Pagrindinis serologinių tyrimų trūkumas yra tas, kad jie neleidžia atskirti aktyvios infekcijos nuo buvusio kontakto su šios ligos sukėlėjais. Laimo boreliozės atveju tai labai svarbu, kadangi endeminiuose rajonuose nuo 1,8 iki 26 proc. sveikų žmonių turi šios ligos sukėlėjų antikūnus dėl buvusios besimptomės infekcijos praeityje. Neįmanoma teisingai interpretuoti LB serologinių tyrimų, nežinant LB paplitimo regione, kuriame šie tyrimai taikomi LB diagnostikai. Šis darbas yra pirmasis Lietuvoje LB sukėlėjų antikūnų paplitimo tyrimas, kuriame nustatytas dviejų pagrindinių erkių pernešamų ligų sukėlėjų antikūnų serokonversijos dažnis tyrimo laikotarpiu, didelio endemiškumo regione, tiriamųjų imtį sudarius atsitiktinės sluoksniuotos atrankos pagal amžių ir lytį principu. Šiame darbe ištirtos įvairių rizikos veiksnių sąsąjos su EE ir LB sukėlėjų paplitimu... [toliau žr. visą tekstą] / TBE is the most common and severe CNS affecting zoonosis. No specific treatment for TBE exists. Tick-borne encephalitis can be prevented by active immunization. Due to governmental financial shortages this vaccination is not included in the national program of imunoprophylaxis for the years 2014-2018. It is very important to find out groups for priority vaccination according to living area, age, leisure activities and occupational risk. Lyme borreliosis diagnosis should be based primarily on the clinical presentation and an assessment of tick exposure risk. In most cases laboratory diagnosis is only supporting clinical picture. Antibody assays still fall short of being completely sensitive and specific to distinguish acute and chronic infection. The diagnostic specificity of serum antibody tests is low because seropositivity in normal population ranges from 1.8% to 26% and LB IgM and IgG may persist for years. The interpretation of serological tests may also lead to misdiagnosis not knowing the seroprevalence of LB in the area. This is the first study of seroprevalence of LB and incidence of TBE and LB during a three year period in Lithuania. The study was conducted in high endemic areas and random samples stratified by gender and age groups were made. Only a few studies perform neutralization tests for detecting TBEV antibodies. Assumed risk factors for the prevalence of TBE and LB were established.

Erkinis encefalitas (EE) – pati dažniausia ir sunkiausia virusinė nervų sistemos infekcija Lietuvoje, kuria per metus vidutiniškai suserga 400 žmonių. Užsikrėtus EE virusu (EEV), galima besimptomė arba klinikinius požymius sukelianti ligos eiga, turinti platų požymių spektrą – nuo lengvos, meningitinės ligos formos iki sunkaus encefalito. Nors mirštamumas nuo EE yra nedidelis, svarbiausia problema – ilgai trunkantis sveikimo laikotarpis ir ilgalaikiai liekamieji reiškiniai, kurie būdingi 26–46 proc. persirgusiųjų. Neaišku, kodėl užsikrėtę identiško virulentiškumo virusu, vieni žmonės perserga besimptome arba lengva EE forma, o kitiems atsiranda sunkus nervų sistemos pažeidimas. Manoma, kad didelę reikšmę turi žmogaus genetiniai veiksniai. Nesant specifinio priešvirusinio EE gydymo, šios sunkios centrinės nervų sistemos infekcijos patogenezės ir genetinių rizikos veiksnių tyrimai yra ypač svarbūs, siekiant nustatyti galimas veiksmingo gydymo paieškos kryptis ateityje. Šio darbo tikslas – nustatyti CCR5 ir TLR3 genų polimorfizmų paplitimą tarp EE sirgusių asmenų ir šių genų polimorfizmų reikšmę polinkiui sirgti EE bei skirtingoms EE klinikinėms formoms išsivystyti. Šis darbas yra didžiausias iki šiol atliktas genetinių veiksnių reikšmės EEV infekcijos metu tyrimas ir pirmasis tokio pobūdžio vaikų tyrimas. Tyrimo rezultatai patvirtino hipotezę, kad nefunkcionuojantis CCR5 ir funkcionuojantis TLR3 yra reikšmingi simptominės EE formos išsivystymo veiksniai, užsikrėtus EEV. / Tick-borne encephalitis (TBE) is the most common and severe viral infection of the central nervous system in Lithuania, with the average number of 400 cases per year. The clinical spectrum of TBE virus infection varies considerably from asymptomatic to mild meningitis or severe encephalitis. Although the mortality of TBE is relatively low, as many as 26–46% of the patients experience long-lasting sequelae. No specific treatment for TBE exists. A most intriguing question is why certain individuals respond with seve¬re clinical symptoms after infection with TBEV while the majority either remains asymptomatic or develops only mild disease. Studies of host genetic susceptibility to infectious diseases aim to in¬crea¬se our understanding of why some individuals are more susceptable than others. Knowledge of genetic susceptibility may be used in develope¬ment of new therapeutic means and also to recognize individuals who are at increased risk of severe symptoms if infected with a pathogen. The aim of this study – to establish the prevalence of the polymorphisms in CCR5 and TLR3 genes in TBE patients and their role in susceptibility to clinical TBE and disease severity. This study is the largest study on the host genetic risk factors predis¬posing to TBEV infection, and the first study of such kind performed in the pediatric population. The results of this study confirmed that a non¬func¬tional CCR5 protein and a functional TLR3 receptor are associated with the clinical expression... [to full text]

Our study was focused on the effect of tick-borne encephalitis virus infection on global gene expression in two human neural cell lines (neuroblastoma and glioblastoma). Changes of gene expression were determined using microarray approach. We identified several genes with up-or down-regulated expression in neural cells following the infection. The changes in expression of some of them were similar in both cell lines,other exhibited different pattern.

This study is focused on changes in protein expression in a glioblastoma cell line during infection with tick-borne encephalitis virus. Newly synthesized proteins were distinguished from previously synthesized proteins using bioorthogonal chemistry (BONCAT method) to observe changes in protein synthesis. Labelled proteins were visualized using two-dimensional PAGE and western blotting followed by Click reaction on membrane. Differences in protein pattern between control and infected cells were observed.

Tick-borne encephalitis virus (strain Hypr) was serially subcultured in PS cells and tick cell line IRE/CTVM19, producing four different viral variants. Biological properties of these new variants were investigated in mouse model. Possible determinants of virulence were found by full-genome sequencing. The role of glycosylation for tick-borne encephalitis virus was evaluated.

Analysis of Spontaneous Adverse Events Reports after Tick-Borne Encephalitis Vaccine Author: Tereza Brázdová Supervisor: PharmDr. Eva Zimčíková, Ph.D. Consultant: PharmDr. Kateřina Malá, Ph.D. Department of Social and Clinical Pharmacy, Faculty of Pharmacy in Hradec Králové, Charles University Introduction and aim: Tick-borne meningoencephalitis is one of the most frequent causes of viral meningitis in Europe. In recent years, the number of cases of this infection in the Czech Republic has begun to rise. Vaccination is the only reliable protection against infection, but it also comes with some risks. Analysis of spontaneous adverse reaction reports is a key source of information for signal detection, which is used to identify drug risks. The aim of this thesis was to analyse the spontaneous reporting of suspected adverse drug reactions (ADRs), using the data from the Central Database of ADRs provided by the State Institute for Drug Control. Methodology: Descriptive statistics were performed from reporting data in the period from June 2004 to October 2017. For example, the total number of reports, the number of ADRs and the patient characteristics were analysed. We compared the adverse reactions with the Vigibase database and evaluated the expectability of reported reactions. Results: During the...

Fästingburet encefalitvirus (TBEV) är ett RNA-virus som tillhör genuset flavivirus. Vid en TBEV-infektion är feber, trötthet, allmänpåverkan samt huvudvärk och muskelvärk vanligt förekommande symtom. Viruset överförs via saliven från fästingar under de första minuterna efter fästingbett. TBEV-IgM och ibland även TBEV-IgG återfinns i serum då symtom i centrala nervsystemet (CNS) yttrar sig i den andra fasen av sjukdomsförloppet. De senaste åren har prevalensen av fästingburen encefalit (TBE) ökat. Sedan 2017 har över 300 fall av TBE rapporterats årligen i Sverige. Laterala flödesanalyser (lateral flow assays, LFA) är billiga, enkla, snabba och baseras på portabla instrument som används bland annat inom biomedicinsk vetenskap. ReaScan® TBE IgM från det finska företaget Reagena är ett snabbtest, baserat på LFA-tekniken, för detektion av TBE-specifika IgM-antikroppar i humant serum och likvor. Syftet med studien var att undersöka om ReaScan® TBE IgM kan användas för att diagnostisera TBE på laboratoriet för Klinisk Mikrobiologi på länssjukhuset i Kalmar. Metodens prestanda undersöktes genom att analysera totalt 23 serumprover, 13 prover från TBE-patienter och 10 prover från icke-TBE-patienter. Sensitiviteten uppskattades genom att analysera 13 serumprover där förekomst av TBE-antikroppar sedan tidigare konfirmerats. Specificiteten uppskattades genom att analysera 10 serumprover från patienter utan känd TBEV-infektion. Den diagnostiska sensitiviteten respektive specificiteten beräknades till 100 %. På grund av den begränsade storleken på undersökningsmaterialet är dock den beräknade sensitiviteten och specificiteten ej helt tillförlitlig. Metodens prestanda ansågs vara tillräckligt god för att den skall kunna användas som en screening-metod för TBEV-IgM-antikroppar på laboratoriet för Klinisk Mikrobiologi på länssjukhuset i Kalmar. / Tick-borne encephalitis virus (TBEV) is an RNA virus that belongs to the genus flavivirus. Symptoms that commonly present during a TBEV infection include headaches, muscle pains, fever and malaise. The virus is transmitted with the saliva from ticks during the first minutes of their blood meal. TBEV-IgM and sometimes TBEV-IgG antibodies can be detected in the patient’s serum when central nervous system (CNS) symptoms present in the second phase of the disease. Over the last couple of years, the prevalence of tick-borne encephalitis (TBE) has increased. Since 2017 over 300 cases of TBE are reported every year in Sweden. Lateral flow assays (LFA) is the technology behind inexpensive, simple, quick and portable instruments that are used within the biomedical science field among others. ReaScan® TBE IgM developed by the Finnish company Reagena is a rapid test, based on the LFA technique, used for the detection of TBEV specific IgM antibodies in human serum and cerebrospinal fluid. The trial aimed to evaluate whether ReaScan® TBE IgM could be used to diagnose TBE at the laboratory of Clinical microbiology at the County hospital in Kalmar. The performance of the test was determined by analysing a total of 23 serum samples, 13 of which consisted of samples from patients with a previously confirmed TBE diagnosis and 10 samples from patients with no known TBEV infection. The diagnostic sensitivity and specificity were both determined to be 100 %. Due to the limited sample size, the calculated sensitivity and specificity are not particularly reliable.  The performance of the test was satisfactory and it could be used as a screening method for the detection of TBEV IgM antibodies at the department of Clinical microbiology at Kalmar County Hospital.