[Detection and antigenic characteristics of the recombinant nucleocapsid proteins of Lassa and Marburg viruses].

Two plasmid vectors, which allow the recombinant polypeptides of Lassa and Marburg viruses to be expressed in prokaryotic cells E. coli strain BL21 (DE3), were produced. The two recombinant polypeptides are able to bind specific antibodies. This provides an opportunity to use them as antigenic components of immunoassay diagnostic test kits.

[Freshwater sponge silicateins: comparison of sequences and exon-intron structure of genes].

Siliceous sponge spicules contain silicateins--proteins taking part in biogenic silica precipitation and determination of the spicule morphological features. The exon-intron structure of four silicatein-alpha isoforms: -alpha1,-alpha2, -alpha3 and -alpha4 from endemic baikalian sponge Lubomirskia baicalensis was studied. For eight sponge species, including both cosmopolitan (Spongilla lacustris, Ephydatia muelleri, E. fluviatilis) and Baikal endemic (L. baicalensis, L. incrustans, Baikalospongia intermedia, B. fungiformis, Sw. papyracea) species, seventeen gene fragment sequences of different silicatein isoforms were determined. It was shown that cosmopolitan and endemic Baikalian sponges differ from each other by gene structure (have different length ofintrons). Among Baikalian sponges silicatein-alpha1 has the most variable intron length, and silicatein-alpha4 is the most conservative. Phylogenetic analysis of amino-acid silicatein sequences allow identify different silicatein isoforms, which authentically differ form four clusters on phylogenetic tree. Phylogenetic analysis of exon-intron sequences gives the possibility to separate different sponge species in the clusters.

[Silicateins identification of the freshwater sponge L. baicalensis].

Siliceous spicules of the freshwater Baikal sponge Lubomirskia baicalensis contain several proteins including silicateins. Existences of four different genes of silicatein alpha (alpha1, alpha2, alpha3, alpha4) which are related to silicatein alpha from the sea sponges were found when cDNA library analysis was made. The intron-exon structure of the full-size silicatein alpha1 gene was determined. This gene has total length of 1988 bp and includes 6 introns (1007 bp) and 7 exons (981 bp). With use of mass-spectrometric analysis of the spicule proteins tryptic digest, two silicateins alpha were authentically found.

[Study of certain indicators of immunity upon infecting CBA/Calac line mice with Lassa virus]. / Izuchenie nekotorykh pokazatelei immuniteta pri zarazhenii myshei linii CBA/Calac virusom lassa]

Some immunity parameters (interferon, tumor necrosis factor, interleukin 1, etc.) were studied in CBA/Calac mice infected with Lassa virus. The results permit a hypothesis that a pathologic inflammatory reaction is responsible for the death of animals in experimental Lassa fever. One of the components of this reaction is endogenous shock involving a manifest production of immune response mediators, such as interferon, interleukin 1. and tumor necrosis factor.

[The localization and preliminary characteristics of antigenic sites (B epitopes) in the nucleocapsid protein of the Lassa virus]. / Lokalizatsiia i predvaritel'naia kharakteristika antigennykh saitov (B-épitopov) v belke nukleokapsida virusa Lassa.

Nucleocapsid protein of Lassa virus contains 4 epitope sites. Three of them were localized in amino acid position 123-1 27, 337-346, and 518-527. Monoclonal antibody 1108 specific to Lassa virus NP-protein reacted with 123-127 synthetic peptide in solid-phase ELISA and precipitated nucleocapsid proteins of Machupo, Tacaribe, and Mopeia arenaviruses in RIP.

[Identification of a protective epitope--a fragment of Lassa virus nucleoprotein]. / Identifikatsiia protektivnogo épitope--fragmenta nukleoproteina virusa Lassa.

Several peptides from Lassa virus glyco- and nucleoproteins were predicted as probable T-cell epitopes. Their synthesis was performed by solid phase method. The study of possible protective effect in vivo with Lassa-sensitive CBA mice revealed protective epitope within the 277-303 nucleoprotein region. Further studies reduced the protective epitope structure to the 287-300 nucleoprotein fragment.

[Recombinant monoclonal antibodies to the Lassa virus: the formation of reactive paratopes]. / Rekombinantnye monoklonal'nye antitela k virusu Lassa: formirovanie reaktivnykh paratopov.

Eighteen hybrid lines secreting recombinant monoclonal antibodies to Lassa virus were produced by fusion of mouse splenocytes with antibody-secreting X-63 myeloma cells. Interrelations between the structure and reactivity of the antibodies were studied by different serological and immunochemical methods. Monoclonal antibodies were divided into different groups according to their serological properties and macromolecular structure. A comparative analysis of the structure and reactivity of the recombinant monoclonal antibodies showed that the light and heavy Ig-specific chains could form the reactive antibodies when the chains were present in different paratopes of Ig molecules.

[The isolation and characteristics of recombinant monoclonal antibodies to the Lassa virus]. / Poluchenie i kharakteristika rekombinantnykh monoklonal'nykh antitel k virusu Lassa.

Recombinant monoclonal antibodies to Lassa virus were produced. The reactivity of the monoclonal antibodies was studied by indirect fluorescence antibody (IFA) technique, enzyme-linked immunosorbent assay (ELISA), and radioimmunoprecipitation method. The observed reactivity did not correlate with IgG isotyping groups.

[Molecular drift of rotavirus during attenuation]. / Molekuliarnyi dreif rotavirusa v protsesse attenuatsii.

The genome structure and polypeptide composition of a rotavirus virion isolated from piglets is described. Proteins p90 and p38 were localized in the external capsid of the virion, and the group-specific antigen of rotaviruses, protein p42, in the internal capsid. Minor polypeptides p116, p98, and p92 were associated with the virus core. A scheme of the structure of porcine rotavirus virion is proposed on the basis of the virion ultrastructure and localization of viral proteins in the capsid. Attention is drawn to the fact that the "wild" strain of swine rotavirus which is virulent for piglets differed in electrophoretic mobility of at least 3 segments of virus genome from the same strain which had undergone 70 passages in cell culture. The virus with altered RNA-segments showed no virulence. The change in the molecular weight of the RNA-segment 4 correlated with the change in polypeptide p90 coded for by it. In the authors' opinion, variability of the major product of protein p90 proteolysis caused the loss of rotavirus virulence for the naturally susceptible host.

[Diagnosis of human rotavirus infection by the dot hybridization method]. / Diagnostika rotavirusnoi infektsii cheloveka metodom tochechnoi gibridizatsii.

The use of the dot-hybridization assay for the diagnosis of human rotavirus infection was shown to be principally possible. 32P-labeled RNA segments of porcine rotavirus transcribed in an in vitro system by activation of endogenous RNA-dependent RNA-polymerase were used as hybridization probes. The transcripts were synthesized to all 11 segments of the parental virus genome. The method proved to be highly specific and very sensitive detecting 10 picograms of viral RNA in fecal filtrates of the patients.

[Monoclonal antibodies to NP protein and their use in studying influenza A viruses]. / Monoklonal'nye antitela k NP-belku i ikh ispol'zovanie dlia izucheniia virusov grippa A.

Monoclonal antibodies to NP-proteins of influenza A/sea gull/Kazakhstan/470/79 (H1N1) virus have been prepared. Each clone interacted with spatially non-overlapping antigenic sites of NP-protein. The clones differed in their capacity to inhibit the polymerase activity of different influenza A virus strains. F-81 clone was shown to interact actively with NP of human influenza A viruses, clone H12 reacted with both human and animal influenza viruses.

[In vitro transcription of human influenza and parainfluenza viruses and its regulation]. / Transkriptsiia in vitro virusov grippa i paragrippa cheloveka i ee reguliatsiia.

The effect of some factors on in vitro transcription of human influenza and parainfluenza viruses was studied. Dinucleotide AfG was shown to stimulate transcription of RNP of human parainfluenza type 3 virus and Sendai virus in the presence of magnesium but not manganese ions same as in the case of influenza viruses transcription. Among two monoclonal antibodies to NP protein of influenza virus, clone F 81 inhibited transcription of RNP of human influenza A viruses, and its influence on transcription of animal influenza viruses was weak. Another clone, H 12, had a low effect. The M protein isolated from influenza and parainfluenza virions inhibited in vitro transcription in the corresponding homologous systems. The inhibiting effect was exerted also by the M protein heterologous to HPIV-3 (M protein of Sendai virus) which suggests the nonspecificity of M protein interaction with transcriptive complexes in large RNA viruses.