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Biomedical subjects

Z I Rovnova

Publications and source records attributed to Z I Rovnova.

At least 19 recordsLinked to original sources
PubMed1986

[Virologic and seroepidemiologic analyses of the circulation of influenza virus A(H1N1), similar to serovariant A(Hsw1N1), in 1984-1985 in Alma-Ata].

The study made with the use of virological, seroepidemiological, radioimmunological and immunological techniques revealed that influenza virus A, antigenically similar to influenza virus A/swine/Iowa/15/30, circulated in Alma-Ata in 1984-1985. The role of these viruses in the seasonal rise of influenza morbidity at the end of 1984 was established. From nasal washings and blood clots obtained from patients, as well as from dissection material, 12 strains were isolated. These strains were similar to serovariant A/swine/owa/15/30 and differed from influenza virus A/New Jersey/76.

Antibodies, Viral↗
PubMed1979

Antigenic determinants in influenza virus hemagglutinin.

Three antigenic determinants were revealed in H3 hemagglutinin of influenza A viruses isolated from 1968 to 1975. One of them was common for all viruses, and two others specified differences between the viruses possessing H3 hemagglutinin.

Epitopes↗
PubMed1977

[Effect of antilymphocyte serum on the course of influenzal infection in mice].

The effect of antilymphocyte serum (ALS) on the course of infection produced by influenza A/PR8/34 virus in mice weighing 10-12 g was studied. Inoculation of mice with ALS produced a longer persistence of influenza virus in the lung tissue and in the blood (up to 15 days of the observation period), whereas in the controls no influenza virus could be isolated after 9 days. No antibody production in ALS-treated mice was observed. The immunosuppression in mice reduced the extent of involvement of the lungs and lethality as compared with the control animals, being conducive to the change of the acute influenza infection into chronic one.

Animals↗
PubMed1977

[Virus-neutralizing properties of rabbit anti-influenzal IgG with a lowered complement-binding and cytophilic activity].

Relationship between the virus-neutralizing property and the effector functions of anti-viral IgG antibody was studied by using rabbit IgG against influenza virus, strain A/PR8/34. The single disulfide bond located in the hinge region of the IgG molecule was reduced to change the effector activity of the antiviral antibody. The reduced antibody retained approximately 50% of the initial complement fixing activity, but lost completely its ability to be fixed in heterologous tissue. When tested in the inhibition-hemagglutination test the reduced antiinfluenza IgG retained complete antigen binding activity. The virus-neutralizing activity of the reduced antiinfluenza IgG (tested on chick embryo) did not differ from that of the crude preparation when 100 EID50 were used. When the dose of the virus was increased up to 1000 EID50 the neutralizing activity of the reduced IgG was found to be less than that of the unreduced one. The results obtained are discussed proceeding from the structural organization of the reduced IgG.

Animals↗
PubMed1977

[Interaction of immune and normal macrophages with the influenza virus].

The interaction of macrophage cultures from immune and non-immune animals with influenza A/PR8/34 virus was studied. Significant differences were demonstrated between immune and normal macrophages. Influenza virus could be found in immune macrophages for a considerably shorter period than in normal macrophages. In immune macrophage cultures as compared with normal macrophages the synthesis of V- and S-antigens occurred only in a small number of cells. The study of the hemadsorbing capacity of macrophages showed the number of cells adsorbing erythrocytes to increase in normal macrophage cultures in contrast to those of immune macrophages. When macrophage cultures were inoculated with influenza virus, it exerted a cytopathic effect on normal macrophages at a lower multiplicity of infection whereas much greater infectious doses were required to produce the CPE in immune macrophages. The experimental results suggest that in infection or immunization certain changes occur in macrophages which may play a role in elimination of influenza virus from the body and in immune response.

Animals↗
PubMedDate not supplied

[Isolation and study of influenza A viruses in different cell cultures].

The usefulness of some cells cultures (BSC-I, VERO, MDSK) for isolation and study of reproduction of influenza A viruses was explored. Out of 50 clinical specimens examined, in 16 cases the virus was isolated both in chick embryos and in MDSK cell cultures. MDSK cultures were found to be highly sensitive to influenza A viruses, which produced cytopathic effect and hemagglutinin accumulation. The plaques formed by freshly isolated strains under an agar overlay containing trypsin were markedly polymorphous. MDSK cells may be recommended for use in virus isolation studies. Examinations of virion morphology revealed their diversity both in size and shape.

Animals↗
PubMedDate not supplied

[Role of phagocytes and antibodies in freeing the body from influenza virus].

Persistence of influenza virus in normal and immune mice was studied by determinations of the virus infectivity and by the immunofluorescence procedures. After intraperitoneal inoculation the virus could be found in macrophages of the peritoneal exudate in both normal and immune animals. However, in macrophages of normal mice synthesis of V- and S-antigens of influenza virus occurred indicating the possibility of virus reproduction in them, whereas in macrophages of immune animals there was practically no synthesis of S-antigen despite a greater number of cells with V-antigen of influenza virus in their cytoplasma. The assumption that elimination of influenza virus from the body is due to specific antibody and immunologically changed macrophage elements is substantiated.

Animals↗
PubMedDate not supplied

[The antigens and nucleotide sequences of influenza A and B viruses in the lymphocytes of human peripheral blood].

Markers of influenza A and B viruses (antigens of hemagglutinin and specific nucleotide sequences) were detected in lymphocyte preparations from normal subjects. The rate of detection of the antigens and specificity (type and subtype appurtenance) of the markers correlated with the influenza epidemic situation. Lower titers of antibodies to the virus whose antigens were present in lymphocytes were observed.

Adult↗
PubMedDate not supplied

[The antigenic characteristics of the influenza virus subpopulations isolated from a single patient].

Examinations by HI and EIA of influenza A (H3N2) virus isolates of 1985-1990 showed the strains derived from nasopharyngeal washings from patients to present very frequently as phenotypic mixtures of stable virus variants. Immunological analysis with monospecific antibody to hemagglutinin antigenic sites revealed a wide spectrum of antigenic activity based on the degree of relationship with viruses of previous years. By means of the immune pressing with antibody of different specificity the isolated strains could be divided into 2 subpopulations each characterized by the presence of only three antigenic sites. The subpopulations homogeneous by the antigenic composition of hemagglutinin represented the strains with antigenic markers of hemagglutinins of previous variants with drift variants of epidemic nature.

Antigenic Variation↗
PubMedDate not supplied

[The detection of the antigens of influenza viruses A and B in the blood of healthy donors].

Blood clots and sera were obtained from donors at a Moscow city transfusion clinic during 1984-1988 and tested by indirect solid-phase enzyme immunoassay with original test-sera to hemagglutinating antigens of influenza A (H1 and H3) and B viruses. Examinations of 1714 blood samples demonstrated hemagglutinating antigens of different specificity (from 0.8% to 35%), the detection rate of one or another antigen correlating with the epidemic activity of influenza virus serovariants A and B. The virus-specific antigens, however, were almost regularly detected in the blood of healthy subjects in the interepidemic seasons as well. The highest number of positive results was observed in tests with blood clot or serum. The results indicate the principal capacity of influenza virus to persist in apparently normal subjects.

Adult↗
PubMedDate not supplied

[The characteristics of the evolutionary variability of influenza A (H1N1) viruses].

Studies of the antigenic structure of hemagglutinins of influenza A (H1N1) viruses isolated in 1978-1988 using monospecific and monoclonal antibodies demonstrated the strains of the H1N1 subtype to be highly apt to antigenic drift. The evolutional variability of that period was peculiar and characterized by antigenic drift in various directions. In those years, the variants were regularly isolated which had retained the determinants of viruses of 1933-1957 circulation period in their hemagglutinin structure. The variants containing in their hemagglutinin 2 antigenic sites common with A/USSR/090/77 virus and antigenic groupings characterizing the strain specificity of each isolate, were epidemically active. At the same time, epidemically important variants were dominant whose properties were markedly different from those of previously known viruses. Their hemagglutinin contained 2 basically new antigenic determinants. This direction of evolutional development of influenza A (H1N1) virus is the most prospective epidemically.

Animals↗
PubMedDate not supplied

[New sites in the hemagglutinin composition of epidemic variants of the influenza virus A (H3N2) from 1989-1990].

Immunological analysis of the antigenic structure of hemagglutinin of newly isolated variants of influenza (H3N2) virus carried out using monoclonal and monospecific antibodies to individual antigenic sites of hemagglutinin showed the 1989-1990 isolates to be markedly different in their antigenic properties from the variants isolated in previous years. Sites with new antigenic properties were determined in hemagglutinin of the isolates. Wide variability was found in the region of three immunodominant sites. The fact of circulation in the human population of influenza viruses of one subtype with different antigenic structures within the limits of one epidemic season was established.

Animals↗
PubMedDate not supplied

[A comparative study of monoclonal and monospecific antibodies in determining the immunodominant antigenic sites of influenza virus A (H3N2) hemagglutinin].

Comparative studies of monospecific (MSA) and monoclonal (MCA) antibodies showed MSA to detect three non-overlapping immunodominant sites on the surface of hemagglutinin (HA) molecule whereas MCA established more subtle differences in HA antigenic structure on the level of epitopes with different immunological significance. The activity of MSA and MCA differed in various tests. While MCA were more active in HI and EIA tests, MSA had a higher neutralizing activity, reducing the infectious virus titre by 5.0-7.5 Ig. Similar reduction of the virus biologic activity was observed only with two MCA whereas the other 20 MCA had a poor neutralizing effect (the virus titre reduction not more than by 2.5 Ig). The employment of MSA and MCA gives most complete information on antigenic restructuring of influenza virus HA at the site level and more subtle structures, epitopes, in the process of evolutionary variability.

Animals↗
PubMedDate not supplied

[Functional activity of glycoproteins from interepidemic isolates of the influenza virus].

The results of the study into the function of glycoproteins of influenza viruses isolated in the 1987 interepidemic period. Natural isolates were found to have virus particles with deficient neuraminidase activity but retained hemolytic and infectious activity. Biological sequences of the lack of neuraminidase activity in the isolates consisted in disorders of sialic acid metabolism in the infected cells, blocking of the receptor site of hemagglutinin and increased sensitivity to inhibitors. It is assumed that the interepidemic virus isolates represent a biologically heterogeneous population in which particles with deficient neuraminidase activity are prevalent.

Animals↗