Innate and adaptive immunity in wild rodents spontaneously and experimentally infected with the tick-borne encephalitis virus.

Two dominant species of wild small rodents trapped in Novosibirsk region, South-Western Siberia, Russia differed in their susceptibility to the tick-borne encephalitis virus (TBEV) infection. TBEV RNA average detection rate for Northern red-backed vole Myodes rutilus (Pallas, 1779) (82.2 ± 5.

[Cytokines and antibodies in experimental infection of wild and laboratory rodents (rodentia) with tick-borne encephalitis virus].

Persistence modeling was performed by means of infection of the wild rodents: northern red-backed vole Myodes rutilus (Pallas, 1779) and striped field mouse Apodemus agrarius (Pallas, 1771), as well as of laboratory mice with the tick-borne encephalitis virus (TBEV) in tick suspensions with subsequent detection of the TBEV, hemagglutination inhibition and virus-neutralizing antibodies, as well as expression of cytokine genes during 4 months. Detection rate of the TBEV RNA and antigen E remained high during the whole period of observations; however, virus pathogenic for laboratory suckling mice was isolated mainly during a period of 8 days post infection. At the late stages of the persistent infection (1-4 months) the TBEV RNA detection rate in northern red-backed voles and laboratory mice remained high, whereas in striped field mice it significantly declined (p < 0.

Tick-Borne Encephalitis Virus Diversity in Ixodid Ticks and Small Mammals in South-Western Siberia, Russia.

Unlabelled: The persistence of tick-borne encephalitis virus (TBEV) in nature is maintained by numerous species of reservoir hosts, multiple transmissions between vertebrates and invertebrates, and the virus adaptation to its hosts. Our Aim: was to compare TBEV isolates from ticks and small wild mammals to estimate their roles in the circulation of the viral subtypes.

Methods: TBEV isolates from two species of ixodid ticks, four species of rodents, and one species of shrews in the Novosibirsk region, South-Western Siberia, Russia, were analyzed using bioassay, hemagglutination, hemagglutination inhibition, neutralization tests, ELISA, reverse transcription with real-time PCR, and phylogenetic analysis.

Evaluation of immune response and protective effect of four vaccines against the tick-borne encephalitis virus.

Among three main subtypes of the tick-borne encephalitis virus (TBEV), the Siberian subtype is currently dominant in a majority of the endemic regions of Russia. However, inactivated vaccines are based on TBEV strains of the heterologous Far Eastern or the European subtypes isolated 40-77 years ago. To analyze the efficacy of the available vaccines against currently prevailing TBEV isolates of the Siberian subtype, mice were immunized subcutaneously three times (one group per each vaccine).

[Detection of the nuclear polyhedrosis virus DNA in samples from eggs and caterpillars at different stages of the gypsy moth Lymantria dispar (L.) population dynamics].

The nuclear polyhedrosis virus (NPV) DNA was detected in samples from eggs and caterpillars of the gypsy moth collected in natural populations of the Western Siberia and Ural by means of PCR with primers corresponding to the polyhedrin gene. According to censuring data, the gypsy moth populations of Western Siberia were at the depression stage. The NPV DNA detection frequencies in eggs (8.

[Changes in the reproduction of tick-borne encephalitis virus in cell cultures].

The currently used tick-borne encephalitis virus vaccines are based on the inactivation of tick-borne encephalitis virus (TBEV) of Far Eastern or West European genetic types from the primary cultures of chick embryo fibroblasts. Since the WHO recommends that vaccines should be designed using continuous cell cultures rather than chick embryos as a substrate, this investigation has compared the infection of continuous monolayer SPEV, Vero E6, and vaccine line Vero (B) cell cultures with TBEV strains of the Siberian and Far Eastern genetic types dominating in the endemic regions of Russia. After cell infection with Far Eastern (Sofyin and 205 strains) or Siberian (Aina, 2530, 2689, and 2703 strains) TBEV genetic types, the viable TBEV titers reached 2.

Multicomponent synthesis of artificial nucleases and their RNase and DNase activity.

The synthesis of new, artificial ribonucleases containing two amino acid residues connected by an aliphatic linker has been developed. Target molecules were synthesized via a catalytic three-component Ugi reaction from aliphatic diisocyanides. Preliminary investigations proved unspecific nuclease activity of the new compounds towards single-stranded RNA and double-stranded circular DNA.

[Phenotypic and genetic characterization of nuclear polyhedrosis virus isolated from gypsy moth (Lymantria dispar L.) larvae from the natural populations of Western Siberia].

Six nuclear polyhedrosis virus (NPV) isolates have been isolated from dead larvae of gypsy moth in Western Siberia. Heterogeneity of virulence and reproduction activity was revealed for the NPV isolated by bioassay with Lymantria dispar L. larvae.

[The effect of fodder on the susceptibility of gypsy moth (Lymantria dispar L.) to nuclear polyhedrosis virus].

Gypsy moth (Lymantria dispar L.) growing on different feeding substrates was shown to affect their susceptibility to nuclear polyhedrosis virus (NPV). The insects feeding on birch leaves had the lowest sensitivity to NPV than those on willow leaves, but the insects growing on pine needles showed the highest susceptibility.

Vertical transmission of tick-borne encephalitis virus between generations of adapted reservoir small rodents.

Vertical transmission of tick-borne encephalitis virus (TBEV) between generations of the small rodents-red voles Myodes rutilus Pallas (previously known as Clethrionomys rutilus Pallas) was shown for naturally infected reservoir hosts and after experimental infection with different sublethal doses of the viral strains. For wild red voles and for their progeny born in 240-280 days after experimental infection of their parents the TBEV was detected in up to 90% of samples by RT-PCR, ELISA and bioassays. Small amounts of the TBEV RNA found in embryos, placenta and blood cells could serve as evidence of prenatal transmission.

Heterogeneity of 3'-Untraslated Region of Genome RNA of the Tick-Borne Encephalitis Virus (TBEV) Strains Isolated from Ticks in the Western Siberia, Russia.

The tick-borne encephalitis virus (TBEV) strains have been isolated from unfed adult ticks Ixodes persulcatus Schulze in Novosibirsk region (South-Western Siberia, Russia) beginning from 1980 till 2006. The TBEV 3'-untraslated region (3'UTR) variable fragment was amplified with primers corresponding to conserved flanking areas. The RT-PCR product lengths varied in range from 100 to 400 bp.

Natural tick-borne encephalitis virus infection among wild small mammals in the southeastern part of western Siberia, Russia.

Infestation of small mammals, including common shrews Sorex araneus L., field mice Apodemus agrarius Pallas, and red voles Clethrionomus rutilus Schreber, with immature Ixodes persulcatus ticks and their infection with tickborne encephalitis virus (TBEV) were studied in the forest-steppe habitat in the vicinity of Novosibirsk, Russia. Larval ticks parasitize all three host species, but virtually all nymphs were found only on field mice and red voles.

[Interrelations between Ixodes persulcatus ticks and the tick-borne encephalitis virus of the red vole (Clethrionomys rutilis) in western Siberia].

We present the data of 12-year survey (1989-2001) of the red vole population in southeastern West Siberia, including estimation of host relative numbers, abundance of immature taiga ticks, and percentage of animals with antigemagglutitnins against tick-borne encephalitis (TBE) virus. We discuss the role of demographic groups of voles as tick's hosts and their participation in the maintenance of TBE causative agent population. The estimation of spontaneous TBE infection rate in summer as well as in winter and early spring seasons, which have been made using a set of molecular-biological, serological and virological methods, demonstrates that a high proportion of red voles maintain non-pathogenic TBE causative agent over a long time, presumably, in the form of persistent infection.

PCR detection of Borrelia burgdorferi sensu lato, tick-borne encephalitis virus, and the human granulocytic ehrlichiosis agent in Ixodes persulcatus ticks from Western Siberia, Russia.

PCR assays were used to test adult Ixodes persulcatus ticks from Western Siberia, Russia, for Borrelia burgdorferi sensu lato, tick-borne encephalitis virus (TBEV), and the human granulocytic ehrlichiosis (HGE) agent. Of the 150 ticks that were studied, 38% were infected with B. burgdorferi, 46% were infected with TBEV, and 8% were infected with the HGE agent.

Behaviour, chemosignals and endocrine functions in male mice infected with tick-borne encephalitis virus.

Odour attractiveness, social behaviour and endocrine status of male mice (outbred ICR strain) were examined 6-7 days after inoculation with subclinical dose of tick-borne encephalitis virus (TBE). According to RT-PCR control of efficiency of infection, males injected with TBE were divided on the two subgroups: TBE+ (males with viral RNA) and TBE- (males without viral RNA). Susceptible males (TBE+ subgroup) showed the higher level of plasma testosterone in comparison with both control and nonsusceptible (TBE- subgroup) males.

[Involvement of the common shrew, Sorex araneus (Insectivora, Soricidae), in circulation of the tick-borne encephalitis virus in south-western Siberia].

We presented the data on the abundance of immature instars of the taiga tick Ixodes persulcatus Schuize on the common shrews Sorex araneus L. in natural foci of tick-borne encephalitis in the south of Western Siberia. Basing on the results of virological and serological studies we demonstrated a low effectiveness of this host species as a donor of disease agent strains, which are predominant in the territory under study, for ticks feeding on shrews.

[Monoclonal antibody study of antigens E and NS1 of Western Siberian tick borne encephalitis virus strains].

Antigenic structure of tick-borne encephalitis virus proteins was studied by ELISA with monoclonal antibodies (MAb) to E and NS1 glycoproteins of strain Sofyin. Envelope proteins appeared to be conservative which corresponded to previously determined nucleotide sequences of E gene fragments and deduced primary structures of the corresponding E protein. Five of six studied MAb to NS1 nonstructural glycoprotein of strain Sofyin reacted with this protein of all studied strains.

Tick-borne encephalitis virus NS1 glycoprotein during acute and persistent infection of cells.

Tick-borne encephalitis virus (TBEV) was propagated in porcine embryo kidney (PS) cells until 48 h whereas human kidney (RH) cells maintained the virus persistence during at least 2 months. One of possible reasons of flavivirus chronic infection might be abnormal NS1 gene expression. Immunoblotting with monoclonal antibodies (MAbs) revealed the similarity of the intracellular and secreted NS1 nonstructural glycoprotein size and linear antigenic determinants in both the infected cell lines.

[Expression of the NS1 gene of tick-borne encephalitis virus in gram-negative bacteria from the mouse nasopharynx].

Bacteria were isolated from the nasopharynx of BALB/c mice and electroporated with pUR290(NS1)2 containing two copies of tick-borne encephalitis virus (TBEV) strain Sofjin NS1 under the control of the lac promoter. The plasmid persisted in transformants for at least ten passages. The NS1 gene expression was detected in Gram-negative enterobacteria via immunoblotting with monoclonal antibodies against TBEV nonstructural glycoprotein NS1.

[Genetic analysis of tick-borne encephalitis virus strains from West Siberia].

Tick-borne encephalitis (TBE) virus strains were isolated in West Siberia in the forest-steppe region near the Ob river in 1981-1992. Hybridization of genome RNA of 46 TBE strains with [32P]cDNA of TBE Sofyin strain revealed essential differences in the genomes of West-Siberian and Far-Eastern Sofyin strains of TBE virus. Nucleotide sequences of 6 TBE strains (1348-1503 n.

Tick-borne encephalitis virus strains of Western Siberia.

Tick-borne encephalitis virus (TBEV) strains were isolated from ticks in Western Siberia for 12 years. Molecular hybridization of the 46 viral RNA with the TBEV cDNA and oligonucleotide probes revealed differences between the Siberian and Far Eastern strains. A comparison of the viral E gene fragment nucleotide sequence showed 89-98% homology between Siberian TBEV strains, whereas their similarity with strains from other populations was less than 83%.

[A comparison of the immune response induced by DNA or by an inactivated vaccine against tick-borne encephalitis].

BALB/c mice were immunized with recombinant plasmid DNA pSVK3-ENS1 and pcDNAI-NS3 containing, respectively, genes E-NS1 and NS3 of tick-borne encephalitis (TBE) virus. Antibodies to TBE virus proteins were detected in the blood sera of the immunized animals by the method of the enzyme immunoassay. Though the titers of virus-specific antibodies in the sera of mice immunized with protein vaccines exceeded those registered after immunization with DNA vaccines, essential protective immunity was observed after the use of both vaccines.

Tick-borne encephalitis virus NS3 gene expression does not protect mice from homologous viral challenge.

Tick-borne encephalitis virus (TBEV) NS3 gene has been subcloned into the expression vector pcDNAI and expressed in eukaryotic cells. Immunization of mice with the recombinant plasmid pcDNAI-NS3 induced antibodies against NS3 protein but did not protect from viral challenge.

[Structural changes in the gypsy moth (Ocneria dispar L.) hemogram in polyhedrosis].

Structural changes in hemogram of Gypsy moth larvae from a population in the phase of quantity increase are studied morphometrically and cytochemically. The counts of granulocytes and prohemocytes are increased, as are the counts of hemocytes possessing phenol oxidase activity and hemocytes reducing nitroblue tetrazolium. Atypical virus morphogenesis is observed.