Differences between HA receptor-binding sites of avian influenza viruses isolated from Laridae and Anatidae.

A comparative study of the hemagglutinin (HA) receptor binding site (RBS) of a number of H13 influenza viruses isolated from Laridae family of birds (gulls) and other influenza viruses obtained from the Anatidae family (ducks) was conducted. The affinity of all viruses to alpha N-acetylneuraminic acid (Neu5Ac alpha), 3'sialyllactose (3'SL), and sialylglycopolymers bearing 3'-sialyl(N-acetyllactosamine) (3'SLN-PAA), [Neu5Ac alpha(2-3)Gal beta(1-4)][-Fuc alpha(1-3)]GlcNAc beta (SLe(x)-PAA), and [Neu5Ac alpha(2-3)Gal beta(1-3)][-Fuc alpha(1-4)]GlcNAc beta (SLe(a)-PAA), was determined. The last three polymer glycoconjugates were synthesized for determining the contribution of carbohydrate chains after the galactose link to the binding with the receptor. The difference in affinity between 3'SL and Neu5Ac alpha in all studied H13 viruses is small, which indicates a less significant role of the galactose moiety in the binding to the receptor. The results of virus binding with polymer sialylglycoconjugates indicates that the method of linking, the third monosaccharide moiety, and the presence of an extra fucose substitute in this moiety may influence the binding considerably. For viruses isolated from ducks, the suitable polymer is SLe(a)-PAA (i.e., a 1-3 linkage between galactose and glucosamine is optimal). This finding is in accord with the data that H13 viruses isolated from the gulls differ based on their ability to interact with polymer sialylglycoconjugates. The affinity to all three polymers is uniform, and the presence of GlcNAc-linked fucose does not prevent the binding. A comparative analysis of six sequenced HA H13 viruses and other subtype viruses showed presence of substantial differences in the composition of amino acids of this region in H13 viruses.

[Spectrum of antibodies to HCV antigens in patients with different clinical patterns of chronic HCV infection]. / Spektr antitel k razlichnym antigenam HCV pri raznykh variantakh techeniia khronicheskoi HCV-infektsii.

Correlations between the spectra of antibodies to HCV proteins represented by various antigenic determinants and clinical variants of chronic HCV infection were studied. Synthetic peptides core-16, NS4-20, and NS5-23 simulating the immunodominant regions of the core, NS4 and NS5 proteins and recombinant proteins core-114 and NS4-86 were used as antigens. The results indicate that if the serum of an HCV patients contains no IgG to both antigenic determinants of NS4 or to NS5 in combination with any core antigenic determinant, a clinical and biochemical remission is highly probable. Chronic hepatitis C is characterized by the presence of IgG in high titers to both antigenic determinants of NS4 protein, particularly in combination with anti-NS5 IgG in low titers or none at all, or high titers of anti-core-16 IgG in combination with high titers of anti-NS4-20 IgG.

[Antigenic specificity of recombinant polypeptides, containing fragments of hepatitis E virus proteins]. / Antigennaia spetsifichnost' rekombinantnykh polipeptidov, soderzhashchikh fragmenty belkov virusa gepatita E.

Antigenic specificity of recombinant polypeptides HE40 and HE60 containing fragments of gene ORF2 and ORF3 protein products of hepatitis E, strain Burma, produced in E. coli cells, is analyzed. Blood sera from patients with acute hepatitis from an endemic region in Uzbekistan were tested for IgG to recombinant antigens by solid-phase enzyme immunoassay with a protein fragment coded by PRF3 gene, a synthetic peptide previously characterized in a commercial test system, as the positive control. 93% sera reacting with recombinant polypeptide HE60 and 32% reacting with HE40 reacted with the synthetic peptide. No antibodies to the studied polypeptides were detected in the sera of Moscow patients with hepatitis A, B, or C confirmed by laboratory findings. Antigenic specificity of recombinant polypeptide HE60 was confirmed by competitive enzyme immunoassay with the same peptide as the competitive antigen. Test system based on recombinant polypeptides HE40 and HE60 was used for deciphering the etiological structure of acute viral hepatitis which occurred in a hepatitis E endemic region of Uzbekistan in 1993.

[Preparation of recombinant polypeptides containing antigenic determinants of hepatitis E virus]. / Poluchenie rekombinantnykh polipeptidov, soderzhashchikh antigennye determinanty virusa gepatita E.

DNA fragments complementary to hepatitis E Burma strain ORF2 and ORF3 obtained by oligonucleotide synthesis were cloned in expressing bacterial system. Recombinant polypeptides isolated from E. coli producer strains, immobilized on solid phase (polystyrene plates and nitrocellulose membranes), are studied in enzyme immunoassay to detect their ability to react with sera of patients with acute viral hepatitis from an Uzbekistan region endemic for hepatitis E. Two polypeptides reacting with the greatest number of sera, containing hepatitis E virus ORF2 and ORF3 gene fragments, were selected for further study of antigenic specificity.

[Analysis of the primary structure of segments of the Karelian fever virus genome]. / Analiz pervichnoi struktury uchastkov genoma virusa karel'skoi likhoradki.

Primary structure of two parts of Karelian fever virus (KFV) genome (29-57 nt and 10507-11591 nt) cloned in recombinant plasmids has been studied and compared with that of Sindbis (HRSP strain) and Ockelbo viruses. Fifty-four nucleotide substitutes were revealed in the sequenced parts of KFV genome including partially 5' and 3'-nontranslated sites ( a total of 1613 nucleotides, or approximately 13.8% of the genome length), in comparison with the Sindbis virus prototype HRSP strain, this being in good correlation with strain variability. Eighteen nucleotide substitutes (96.4% homology) were detected in the NSP1 gene site (60-557 nt) of KFV in comparison with Sindbis virus and only 5 substitutes (98.8% homology) vs. Ockelbo virus. These data on primary structure of KFV genome reliably and unambiguously indicate the appurtenance of this virus to Sindbis-like viruses.

[An analysis of the amino acid sequence of the heavy subunit of the hemagglutinin in influenza virus A/Alma-Ata/1417/84]. / Analiz aminokislotnoi posledovatel'nosti tiazheloi sub''edinitsy gemaggliutinina virusa grippa A/Ama-Ata/1417/84.

An analysis of the amino acid sequence of influenza A/Alma-Ata/1417/84 (H1N1-Hsw1N1 serovariant) virus hemagglutinin heavy chain deduced from the nucleotide sequence of cloned full-size DNA complementary to the 4th segment of genome RNA was carried out. Unlike A/New Jersey/8/76 virus, the hemagglutinin of the virus under study was found to be more similar in the rate of HA1 homology, amino acid sequence of the signal peptide, antigenic sites Sa, Ca, and the receptor-binding site to human influenza viruses isolated in the 1930-1980-ies, in particular to influenza A/Taiwan/1/86 virus. It is assumed that an influenza virus more adapted to the human population like the strain A/Alma-Ata/1417/84 may be an etiological factor of a new influenza pandemic.

[Synthesis, cloning, and determination of the primary structure of a full-length DNA copy of the gene for influenza A/Alma-Ata/1417/84 virus (H1N1-serovariant HSW1N1) hemagglutinin]. / Sintez, klonirovanie i opredelenie pervichnoi struktury polnorazmernoi DNK-kopii gena gemaggliutinina virusa grippa A/Alma-Ata/1417/84 (N1N1-serovariant HSW1N1).

The full-length copy of the hemagglutinin gene RNA of the influenza virus A/Alma Ata/1417/84 (Hsw1 N1-serovariant) has been synthesized and cloned on Escherichia coli plasmid pBR327. The complete nucleotide sequence of the cloned DNA copy was determined by the Maxam-Gilbert procedure. The predicted amino acid, sequence of HA1 hemagglutinin subunit was compared with the sequences of HA1 subunits from other H1N1-subtype influenza virus strains. It has been found that the structure of the HA1-subunit of the studied strain is most similar to the structure of the identical region of the A/New Jersey/18/76 hemagglutinin.

[Primary structure of the gene for protein VP1 from foot-and-mouth disease virus serotype O1 isolated in the USSR]. / Pervichnaia struktura gena belka VP1 virusov iashchura serotipa O1, izolirovannykh v SSSR.

The nucleotides sequence has been determined for the viral RNA and some of its cDNAs coding for the major antigenic protein of the epidemic stomatitis O1-194 and O1-1618 VP1 viruses. The expressed microheterogeneity has been registered for the population of the strain O1-194.

[The primary structure of the hemagglutinin of influenza A (H3N2) viruses isolated in the USSR in 1985]. / Pervichnaia struktura gemaggliutinina virusov grippa A (H3N2), izolirovannykh v SSSR v 1985 g.

The primary structure of hemagglutinin of the members of three main antigenic groups of current influenza A (H3N2) viruses was determined. A phenomenon of "antigenic mimicry" was found to be due to the accumulation of reversions in hemagglutinin structure at late stages of antigenic drift.

[Structure of the hemagglutinin gene of the influenza virus during serial passages in chick embryos]. / Struktura gena gemaggliutinina virusa grippa pri seriinykh passazhakhna kurinykh émbrionakh.

The sequence analysis of HA gene of passaged variants of A/USSR/2/85 influenza virus was carried out. It was shown that in the process of passage of virus in chick embryos the structure of HA gene was not changed. These data correlated with those obtained early during investigation of A/Leningrad/337/76 influenza virus by the oligonucleotide mapping.

[Changes in the amino acid sequence of hemagglutinin during sequential adaptation of human influenza virus A to replication in mice]. / Izmeneniia aminokislotnoi posledovatel'nosti gemaggliutinina pri posledovatel'nykh étapakh adaptatsii virusa grippa A cheloveka k razmnozheniiu v organizme myshei.

The primary structure of hemagglutinin (HA) gene of Influenza virus A/USSR/90/77 (H1N1) variants after 3 and 11 passages has been determined. In the HA1 coding region of mice-adapted virus (11 passages) there are two amino acid substitutions: Thr 89----Ala and Asn 127----Asp. At the first stage of adaptation (3-rd passage) only a single mutation was detected: Asn 127----Asp. The adaptation is accompanied by the loss of specific carbohydrate attachment sites adjacent to the receptor-binding site located at HA1 subunit with a concomitant variation in antigenicity.

[Primary structure of the full-length DNA copy of the neuraminidase gene in the avian influenza virus of the N7 antigenic subtype]. / Pervichnaia struktura polnorazmernoi DNK-kopii gena neiraminidazy antigennogo podtipa N7 virusa grippa ptits.

Complete nucleotide sequence of the cloned full-length DNA copy of the influenza virus A/FPV Weybridge (H7N7) neuraminidase gene has been determined.