[Methods for the Crimean-Congo hemorrhage fever diagnosis]

Several distinct methods currently used for the Crimean-Congo Hemorrhage Fever diagnosis (CCHF) were suggested in this work. We demonstrated that the ELISA-based diagnostic kits, which are based on CCHFV recombinant antigens produced in E. coli cells, still possessed a few substantial shortcomings, which are yet to be addressed. In this work we presented the development of the unique CCHFV detection system fully based on reverse transcription--nested two-step polymerase chain reaction (RT-PCR). Our RT-PCR-based diagnostic kit for the CCHFV detection is now commercially available. We also developed a simple screening method for the samples, potentially containing CCHFV, which is based on restriction fragment length polymorphism (RFLP) amplicons analysis and allows for preliminary genotyping of the CCHFV isolates.

[The production of high-yielding strain of rubella virus from wild type virus extracted from a patient in the Western Siberia in 2006]

The study was targeted to investigate the propagation of rubella virus in the cell cultures of various origins and with different cultivation methods. The high-yielding strain of rubella virus was produced. The "spinner-culture" cultivation method was applied and the strain's RNA was detected in 10-8 dilution in real time mode. This strain is supposed to be used in preparation of the standard antigen to implement in the development of immune enzyme test system targeted to the rubella virus specific antibodies.

[Entification of the Rubella virus genotype 1H in Western Siberia]

Molecular epidemiological study of novel strain of Rubella virus isolated during the outbreak in Western Siberia in 2004 was described. Detailed phylogenetic analysis performed based upon entire SP-region, which encodes all three Rubella structural proteins (C, E2, and E1), was implemented. This analysis provides characterization of this strain and classifies it as 1H genotype, thereby correcting previous classification of this strain based upon shorter nucleotide sequence, only encoding E1 protein. Therefore, this study identified the genotype of the Rubella virus not previously detected in Western Siberia (and even entire Russian Federation), which highlights the importance of more extensive characterization of genetic variability of the Rubella virus, especially with regard to potential influence of vaccination on the Rubella virus mutagenesis.

[Differentiation of genetic variants of Crimean-Congo hemorrhagic fever virus]

The paper describes a simple, rapid screening of samples potentially containing Crimean-Congo hemorrhagic fever (CCHF) virus strains, by applying the restriction analysis of amplicones, for the differentiation of CCHF virus genotypes that are characteristic of Europe from virus biovariants uncharacteristic of this area, this technique requiring no sequence at the first stage. For this screening, the authors propose to use the PCR fragment of CCHF L segment that comprises a variable region, as well as Alul and Haelll restriction endonucleases. The screening scheme proposed for samples potentially containing CCHF virus may aid investigators to monitor in order to detect uncharacteristic genotypic virus variants in the Russian Federation and other European countries.

Rational design based synthetic polyepitope DNA vaccine for eliciting HIV-specific CD8+ T cell responses

Advances in defining HIV-1 CD8+ T cell epitopes and understanding endogenous MHC class I antigen processing enable the rational design of polyepitope vaccines for eliciting broadly targeted CD8+ T cell responses to HIV-1. Here we describe the construction and comparison of experimental DNA vaccines consisting of ten selected HLA-A2 epitopes from the major HIV-1 antigens Env, Gag, Pol, Nef, and Vpr. The immunogenicity of designed gene constructs was assessed after double DNA prime, single vaccinia virus boost immunization of HLA-A2 transgenic mice. We compared a number of parameters including different strategies for fusing ubiquitin to the polyepitope and including spacer sequences between epitopes to optimize proteasome liberation and TAP transport. It was demonstrated that the vaccine construct that induced in vitro the largest number of [peptide-MHC class I] complexes was also the most immunogenic in the animal experiments. This most immunogenic vaccine construct contained the N-terminal ubiquitin for targeting the polyepitope to the proteasome and included both proteasome liberation and TAP transport optimized spacer sequences that flanked the epitopes within the polyepitope construct. The immunogenicity of determinants was strictly related to their affinities for HLA-A2. Our finding supports the concept of rational vaccine design based on detailed knowledge of antigen processing.

[Genotyping of rubella virus circulating in Western Siberia of Russia during 2004-2006 epidemic period]

Twenty one strains of rubella virus were isolated in the Western Siberia during 2004-2006 epidemic period. Genotyping of isolated strains was performed by partial sequencing of glycoprotein E1 gene. Phylogenetic analysis showed that 20 out of 21 isolated in the Western Siberia strains of rubella virus belonged to genotype 1g, and 1 strain (isolated in Altai region in 2006)--to genotype 1E.

[Analysis of genomes of two rubella virus strains from the 2004-2005 outbreaks in West Siberia]

Two outbreaks of rubella infections notified in the Tomsk and Kemerovo Regions were investigated. Two rubella virus strains from one patient in each outbreak were isolated and genetically characterized. Reverse transcription polymerase chain reaction was used to reveal partial E1 gene sequence at a length of 915 nucleotides. Analysis indicated that the rubella virus strains circulating in the West-Siberian region belonged to international genetic 1g group, which had been first detected in Russia.

[Genomic S segment of Crimean-Congo hemorrhagic fever virus circulating in Russia and Bulgaria]

S-segment nucleotide sequences for two Crimean-Congo hemorrhagic fever (CCHF) virus strains isolated in the Rostov Region of Russia and in Bulgaria have been determined. Analysis of complete S-segment nucleotide sequences in the viral strains from different regions of the world has established that the CCHF virus strains isolated from ticks and human beings in different southern Russian regions in 1967 and 2000 are very closely genetically and they form an individual subgroup in the basic European genetic group. By the S-segment structure, the CCHF virus strain isolated in Bulgaria in 1978 belongs to the same genetic group as a representative of its second subgroup. Analysis of the S-segment 3'-noncoding region suggests that the CCHF virus circulating in Europe, Central Asia, and China may have originated from one global focus of infection, including several CCHF virus genovariants. During evolution, fragmental exchange apparently occurred in the S-segment 3'-noncoding region as a result of homological recombination.

[Genetic monitoring of the Crimean-Congo Hemorrhagic Fever virus in Kazakhstan and Tajikistan in 2001-2003]

Blood specimens obtained from 32 CCHF patients were tested for the presence of CCHF virus markers. In addition, 3210 ticks of the genera Hyalomma asiaticum, Hyalomma anatolicum, and Dermacentor niveus were examined to identify the CCHF virus antigen and RNA. This material was obtained during the 2001-2003 local outbreaks of CCHF in Kazakhstan and Tajikistan. The nucleotide sequence in the region 983-1282 of S segment of the CCHF virus for 12 wild type strains was determined. The phylogenetic relationships among the established biovariants of CCHF virus, and also between these biovariants and those from other regions of the world were identified. We were the first to demonstrate the presence of an African-like genotype of CCHF virus in the territory of Kazakhstan. The conclusion was made that two genotypes of CCHF virus were in circulation in Kazakhstan. It was also demonstrated that CCHF virus, circulating in the territories of Kazakhstan and Tajikistan, was genetically heterogeneous.

Complete L segment coding-region sequences of Crimean Congo hemorrhagic fever virus strains from the Russian Federation and Tajikistan

The large (L) RNA segment of Crimean Congo hemorrhagic fever (CCHF) virus strain AST/TI30908, isolated from pooled Hyalomma marginatum ticks collected in 2002 from the Astrakhan region of European Russia, was amplified piecemeal using reverse-transcription/polymerase chain reaction, followed by direct sequencing of gel-purified amplicons. After removal of 5' and 3' primer-generated termini, the assembled AST/TI30908 L segment sequence is 12112 nucleotides long, with 41.3% G + C content, and is greater than 87% and 96% identical at the nucleotide and translated amino acid levels, respectively, to partial or full-length CCHF virus L segment sequences deposited in GenBank. A complete L segment coding-region sequence for CCHF virus strain TAJ/HU8966, isolated from a patient in Tajikistan in 1990, was determined in a similar fashion. This L segment (12133 nucleotides long, 41.1% G + C content) shares 88% nucleotide identity with the full-length strain Matin from Pakistan, and 97% nucleotide identity with a partial L segment sequence of strain Khodzha from Uzbekistan. Strain TAJ/HU8966 shares at least 96% identity at the translated amino acid level with all other CCHF virus L segment sequences. Although, for the most part, CCHF virus L polyprotein primary sequences are uniformly well conserved, a region of marked variability was identified in the N-terminal half of the RNA-dependent RNA polymerase. This region, approximately 50 amino acids in length, is flanked by previously-reported arenavirus and bunyavirus-conserved regions, and may prove useful in CCHF diagnosis and viral taxonomy.

[ELISA and RT-PCR-based research of viruses in the ticks collected in the foci of Crimean-Congo fever in Kazakhstan and Tajikistan in 2001-2002]

Different species of ticks were found, in the territories of Kazakhstan and Tajikistan, to be infected with the virus of Crimean-Congo hemorrhagic fever (CKHF). The virologic evaluation included determination of antigen and RNA of the CKHF virus by ELISA and RT-PCR, respectively. The below tick species were found to be involved in the epidemic process: Hyalomma asiaticum, Dermacentor niveus (Kazakhastan) and Hyalomma anatolicum (Tajikistan). The results testify to the fact that Hyalomma ticks are the main carrier of the above virus in the Middle Asia. At the same time, Dermacentor niveus ticks are infection carriers in Kazakhstan.

[Study of virus contamination of Ixodes ticks in the foci of Crimean-Congo hemorrhagic fever in Kazakhstan and Tajikistan]

The data on the contamination of different of ticks with Crimean-Congo hemorrhagic fever (CCHF) virus on the territory of Kazakhstan and Tajikistan were obtained. The methods of the evaluation of the virus contamination of ticks included the determination of the antigen and CCHF virus RNA by the methods of the enzyme immunoassay and the reverse transcription PCR respectively. Different tick species were found to be involved in the epidemic process: Hyalomma asiaticum, Dermatocentor niveus (Kazakhstan) and Hyalomma anatolicum (Tajikistan). The results obtained in this study confirmed that the main vector of CCHF virus in Central Asia were ticks of the genus Hyalomma, and in Kazakhstan the vectors of this virus also included ticks Dermatocentor niveus.

Genetic analysis of the M RNA segment of Crimean-Congo hemorrhagic fever virus strains involved in the recent outbreaks in Russia

Crimean-Congo hemorrhagic fever (CCHF) is a severe zoonosis with a high fatality rate. In Russia, local CCHF outbreaks have occurred in the Stavropol Territory, and the Volgograd and Astrakhan Regions during 2000 and 2001. Seven strains of CCHF virus (CCHFV) were isolated from infected patients and collected ticks. Two fragments of the CCHF virus M genome segment were PCR amplified and their nucleotide sequences were determined. All these virus strains appear to be closely related (up to 5.8% nucleotide sequence differences) and form a distinct clade on the CCHFV phylogenetic tree. Within this clade, CCHFV strains from Stavropol and Astrakhan cluster together, whereas those from Volgograd form a separate subgroup.

[The study of orthopoxvirus genes for Kelch-like proteins. II. Construction of cowpox virus variants with targeted gene deletions]

Integrative plasmids p delta C, p delta D, and p delta G were designed to contain a selective marker beyond the region of homology to virus DNA and to allow construction of recombinant cowpox viruses (CPV) that lack C18L, D11L, or G3L coding for kelch-like proteins. CPV mutants lacking one (C18L, D11L, or G3L), two (D11L/G3L or C18L/D11L), or three (D11L/G3L/C18L, that is, all) kelch-like protein genes of the left variable region of the virus genome were obtained. Impaired reproduction was observed for the triple mutant. Pocks produced by the triple mutant and the original virus differed in size and morphology. In addition, the two CPV variants differed in destructive changes caused in the chorioallantoic membrane of chicken embryos.

[Genetic identification of the Crimean-Congo hemorrhagic fever virus during epidemic outbreak in Kazakhstan in 2000]

Sera samples from patients suspected of Crimean-Congo hemorrhagic fever (CCHF) taken during epidemic outbreak at the territory of Sarysusky and Moiynkumsky districts of the Zhambyl region in Kazakhstan, in 2000, were analysed by means of reverse transcription-polymerase chain reaction (RT-PCR) and sequencing of virus genome fragments. Genome RNA of CCHF virus was found in 2 assays. Analysis of nucleotide sequences of fragments of S-segment of viral genome revealed in the Sarysusky districts circulation of CCHF virus, genetically resembled to close phylogenetically to CCHF virus strains from China.

[Genetic characteristics of the S-segment of RNA from two strains of the Crimean-Congo hemorrhagic fever virus isolated in the south of Russia and in Uzbekistan]

Complete S-segment nucleotide sequences of genomic RNA were determined for two Crimea-Congo hemorrhagic fever (CCHF) virus strains, i.e. LEIV 10145 Uz isolated from ticks in Uzbekistan, 1985, and LEIV 29223 Stv isolated from a patient in Stavropol region, 2000. It was established that the S-segment length is 1672 and 1674 nucleotides. Therefore, the initiating codon (for methionine) is located at positions 56-58; the length of translation frames for the nucleocapsid protein is 482 amino acid residues. Distinctions in the length of S-segment, as compared to other strains, are related only with the 5' and 3' non-coding regions. A comparison of the nucleotide and amino-acid sequences of S-segments of genome of the mentioned strains with the early published data showed that the CCHF virus strain isolated in Uzbekistan is mostly close to strains isolated in China, and that the strain isolated in Stavropol region forms, jointly with Drozdov strain isolated in the Astrakhan region, a separate branch in the phylogenetic tree.

[Characteristics of Crimean-Congo hemorrhagic fever virus circulating in Russia and Central Asia]

Five antigen-positive samples isolated from patients with Crimean-Congo hemorrhagic fever (CCHF) and from Hyalomma marginatum ticks collected in the European part of Russia and three laboratory strains of CCHF isolated in Russia, Uzbekistan, and Tadjikistan were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) and sequencing. Comparison of nucleotide sequences of fragments of CCHF virus genome S segment and phylogenetic analysis of Russian strains showed that all CCHF strains isolated from humans and H. marginatum circulating in Russia were closely related and differed essentially from CCHF variants from other regions. Strains isolated in Uzbekistan and Tadjikistan were most closely related to CCHF strains from China.

[Selective stabilization of AT-rich DNA duplexes by oligodeoxyribonucleotide conjugates with distamycin analogues]

Oligodeoxyribonucleotide conjugates with distamycin analogues containing up to five pyrrolecarboxamide moieties were synthesized. The stability of duplexes formed by these conjugates was shown to depend directly upon the number of pyrrolecarboxamide moieties in the ligand molecule. For the duplexes formed by octaadenylate and octathymidilate conjugates with the distamycin pentapyrrole analogue, stability was demonstrated to be achieved by either one or two ligand molecules; however, duplexes containing two ligand molecules are more stable.

[Expression of synthetic gene for human angiogenin in E. coli cells]

A synthetic gene for human angiogenin was cloned into pRTang under control of the Proteus mirabilis recA promoter. After induction with mitomycin C, Escherichia coli cells transformed with pRTang produced an additional 14.2-kDa protein. According to electrophoretic and immunochemical analyses, this protein was identical to human angiogenin.

Comparative studies of gamma-interferon receptor-like proteins of variola major and variola minor viruses

To study specific properties of the human gamma-interferon (gamma-IFN) receptor-like proteins of the highly virulent and low virulent strains of variola (smallpox) virus (VAR) recombinant plasmids determining synthesis of these proteins in E. coli cells have been constructed. The recombinant viral gamma-IFN receptor-like proteins have been found to have high interferon-neutralising activity with regard to human gamma-IFN but not murine gamma-IFN and human alpha-IFN. The variola major and variola minor proteins under study do not differ in the efficiency of human gamma-IFN antiviral activity inhibition.

[Chemico-enzymatic synthesis, cloning and expression of a gene for an analog of human anaphylatoxin C5a]

Chemical-enzymatic synthesis and cloning of a gene for a human anaphylatoxin C5a analog were carried out. Recombinant plasmid pRC5a providing the expression of the synthetic gene in the Escherichia coli cells was obtained. The biological activity of the expression product was demonstrated by the chemotaxis activity test and by the release of myeloperoxidases from rat peritoneal cells that was induced by bacterial cell lysates containing the recombinant protein.

[Preparation of hybrid proteins consisting of human interleukin-2 and the cytotoxic A-subunit of Shigella toxin]

Recombinant plasmids providing the synthesis of chimeric proteins consisting of amino acid sequences of human interleukin-2 (IL-2) and Shiga toxin cytotoxic A-subunit (ILA and AIL chimeric toxins) were constructed. The ILA and AIL chimeric toxins were shown to inhibit protein synthesis in the rabbit reticulocytes cell-free system. These chimeric toxins displayed two opposite activities of the constituent parts of their molecules on T-lymphocytes from the peripheral blood of healthy volunteers. Hybrid protein AIL (approximately 10(-6) g/ml) has caused the most significant depression of T-lymphoblast proliferation.

[Localization of the N-terminal epitope of the HBe antigen of the hepatitis B virus]

A new antigenic site was located at the N-terminus of HBeAg. Comparison of antigenic properties of the recombinant proteins HBeAgR and HBeAg delta N truncated at the N-terminus has lead to this conclusion. The proteins have been studied by ELISA and western-blot analysis using monoclonal antibodies E1A7 and polyclonal antiserum to HBeAg. Polyclonal antiserum to HBeAg binds to HBeAg delta N and HBeAgR while monoclonal antibodies E1A7 interact only with HBeAgR. The data obtained supports evidence that the epitope is located at the N-terminus of HBe-polypeptide chain. It is classified as a sequential type one and at least one amino acid from the Met-Asp-Ile sequence participates in its formation.

[Effective expression of genes for interleukin-2 and its mutant analogs in E. coli cells]

Recombinant plasmids were constructed for the efficient expression in E. coli cells of the human interleukin-2 (HIL-2) gene and two its mutant analogues obtained by of chemical-enzymic synthesis and polymerase chain reaction (deletion of 14 C-terminal amino acids and a change of the codon for Trp121 to Phe). The recombinant HIL-2 but not the mutant analogues were shown to be biologically active. Both analogues obtained were weak antagonists to HIL-2.

[Effective synthesis and cloning of the human interleukin-2 gene and its analog: expression of the interleukin-2 gene in E. coli cells]

Artificial DNA fragments encoding human interleukin-2 (133 a.a.) and its analogue (deletion of 14 C-terminal a.a.) were prepared by means of the DNA polymerase I mediated extension of synthetic polynucleotides having short overlapping sequences at their 3'-ends. The fragments were cloned in specially designed pFH-type plasmids and then excised by the FokI and other restriction endonucleases to yield the subfragments with the structurally predetermined 5'-unique cohesive ends. The complete synthetic gene was constructed by one or two-step ligation. The expressed IL-2 was tested by analysing the T-cell proliferation activity of E.coli crude lisates containing the pEXIL2 expression plasmid.

[Reconstruction of the synthetic gene for human interleukin-2]

Chemical-enzymatic synthesis and cloning of the DNA fragment coding for the human interleukin-2 signal sequence was accomplished. A hybrid plasmid pSIL-2 containing the gene of the human interleukin-2 with this signal sequence was constructed for effective expression of the gene in eukaryotic systems. A variant permitting the removal of the interleukin-2 stop-codons was obtained, which is suitable for the construction of chimeric genes containing the interleukin-2 gene sequence at the 5'-end.