[The immunoenzyme test system for detection of HIV-1 antigens based on using immune polyclonal anti-HIV serum and monoclonal antibodies against gene GAG HIV-1 proteins]. / Immunofermentnaia test-sistema dlia vyiavleniia antigenov VICh-1, osnovannaia na primenenii immunnoi poliklonal'noi anti-VICh syvorotki i monoklonal'nykh antitel k belkam gena GAG VICh-1.

The paper describes the enzyme immunoassay system for detection of human immunodeficiency virus antigens, which is based on the use of rabbit anti-HIV antibodies and monoclonal antibodies to HIV-1 gene proteins gag. The system may be useful in the examination of laboratory and clinical samples to reveal both free and conjugated antigens in the composition of immune complexes. The sensitivity of the assay system under development is 0.5 ng/ml at 100% specificity.

[The antigenic and immunogenic properties of a recombinant protein of the HIV-1 gag-pol gene secreted by Saccharomyces cerevisiae yeast cells]. / Antigennye i immunogennye svoistva rekombinantnogo belka gena gag-pol VICh-1, sekretiruemogo drozhzhevymi kletkami Saccharomyces cerevisiae.

Analysis of the immunological properties of recombinant proteins of HIV-1 gene gag-pol secreted by yeast cells S. cerevisiae was carried out. The proteins under study interacted with antibodies from HIV-1-seropositive human subjects and with antibodies of rabbit immune serum to the native virus as effectively and specifically as natural HIV-1 proteins. The yeast gag-pol-protein complex was markedly immunogenic and induced in animals synthesis of antibodies of a certain specificity spectrum. A comparative immunochemical analysis of the properties of the recombinant proteins carried out by EIA and immune blot showed a certain degree of similarity between the yeast proteins and those of analogous construction produced in E. coli system.

[Masking of HIV antigen by specific antibodies in a model experiment]. / Maskirovanie antigena virusa immunodefitsita cheloveka spetsificheskimi antitelami v model'nom éksperimente.

An immuno-diagnostic test system of competitive EIA detecting HIV antigen in a concentration up to 1 ng/ml has been developed. Using this system, a phenomenon of binding of HIV antigen by antibody in sera from infected persons consisting in masking of antigenic determinants was demonstrated. The "undetectability" of HIV antigen in the system of competitive EIA caused by this phenomenon is considered to be a model of clearance of antigen at the excess of antibody in vitro. The experimental results are in agreement with the suggestion that repeated HIV antigenemia occurs as a result of exhaustion of specific immune responses.

[Biological activity of human alpha-interferons studied using specific antisera]. / Issledovanie biologicheskoi aktivnosti chelovecheskikh al'fa-interferonov pri pomoshchi spetsificheskikh antisyvorotok.

Preparation of highly active rabbit antisera (AS) to human recombinant alpha 2-interferon and their use for studying biological properties of natural and plasmid alpha-interferons are described. By exhaustion of AS by alpha 3-interferon there were prepared practically monospecific AS not reacting with antigenic determinants of alpha 3-interferon. It was found that alpha 3-interferon represented a significant portion of human lymphoblastoid interferons and was included in PH-labile alpha-interferon from serum of patients with Kaposi carcinoma. AS to alpha 2-interferon completely neutralized antiviral and antiproliferative activity of the homologous subtype alpha-interferon and stimulation of cytotoxicity of human natural killer cells induced by it. It neutralized also the same effects of the heterologous subtypes (alpha 3 and alpha F/D) and leukocytic interferon, but the neutralization level was lower. The results of the study confirmed the polyfunctional nature of the interferon molecule.

[Changes in natural killer activity in the influenza virus infection of mice and in treating lymphocytes with the influenza virus and its proteins in vitro]. / Izmenenie aktivnosti estestvennykh killerov pri zarazhenii myshei virusom grippa i pri obrabotke limfotsitov virusom grippa i ego belkami in vitro.

Changes in the activity of natural cytotoxic lymphocytes (natural killers, NK) were studied in the course of infection of CBA mice with a mouse-adapted or unadapted (epidemic) variants of influenza A/USSR/90/77 virus. The activity of NK against K562 target cells in the peripheral blood, lungs, and spleens was found to increase considerably 18 hours after intranasal inoculation with any of the variants and to persist at a high level for up to 72 hours. Virus replication in the lungs and peripheral blood was observed only in mice infected with the adapted virus variant. A conclusion was drawn that the increase in NK activity in the organs of influenza virus-infected mice was nonspecific providing no protection against a fatal outcome after infection with the mouse-adapted (pathogenic) virus. Treatment of lymphocytes recovered from the peripheral blood, lungs, and spleens of infected and non-infected mice in vitro with preparations of intact viruses and isolated viral proteins exerted different effects on the NK activity: enhancement after treatment with intact viruses and inhibition by isolated viral proteins. The effect did not depend on the virulence of the strain from which viral proteins were isolated. The importance of the phenomenon of different modulating effect of influenza virus and its structural proteins on the NK activity is discussed.

[Demonstration and study of the internal proteins of the influenza B virus using solid-phase radioimmunological analysis]. / Indikatsiia i izuchenie vnutrennikh belkov virusa grippa B s pomoshch'iu tverdofaznogo radioimmunologicheskogo analiza.

Internal proteins of influenza B/USSR/14/80 virus retaining their antigenic and immunogenic activities were obtained by electrophoresis in 1% agarose. Antisera to eluted NP and M polypeptides were prepared. Study of influenza B viruses isolated in 1940-1984, performed by solid-phase radioimmunoassay, revealed no differences in the antigenic properties of nucleoprotein and matrix protein, except in the B/Yamagata/73 virus.

[Identification of influenza virus type A by solid-phase radioimmunological analysis]. / Identifikatsiia virusa grippa tipa A metodom tverdofazovogo radioimmunologicheskogo analiza.

High sensitivity and specificity of solid-phase radioimmunoassay (SPRIA) in identification of influenza A (H1N1 and H2N2) viruses in the infected allantoic culture were demonstrated. Mixtures of influenza hyperimmune sera free from antibodies to host cell antigens and antineuraminidase antibodies were used as active test sera. The test serum a-H1N1 consisted of antisera to A/FmI/47, A/Netherlands/36/56, and A/USSR/090/77 strains; it detected practically all tested variants of H1N1 virus isolated in 1947-1982 in allantoic cultures containing virus-specific protein in amounts of 1.4 to 0.7 ng/ml. For the detection of H2N2 subtype viruses (1957-1967), a mixture of antisera to A/Singapore/1/57, A/Leningrad/2/63, A/Gorkiy/62/65, and A/Tokyo/3/67 viruses was used. This test serum could detect H2N2 virus in the allantoic fluid containing 0.7-035 ng/ml of virus protein.

[Test system for detecting and differentiating the influenza virus by an immunoenzyme method]. / Test-sistema dlia indikatsii i differentsiatsii virusa grippa immunofermentnym metodom.

Detection and differentiation of small amounts of influenza A and B viruses was done by enzyme-immunoassay based on detection of the complex of internal proteins. It was shown that two kinds of sera to the complex of internal proteins could be used: sera against disrupted viruses grown in a different system (mice or cell culture) and containing almost no CAM component for virus detection in the allantoic fluid of chick embryos, and sera to preparations of viruses grown in chick embryos and disrupted with detergents for elimination of virion surface determinants (wastes of subunit vaccine) for virus detection in nasal secretions of vaccinated subjects. The test-systems containing antibodies to the complex of internal proteins were shown to be as sensitive and specific as those containing antibodies to pure M protein and RNP.

[Use of agarose for isolating influenza virus proteins retaining a high immunogenicity]. / Ispol'zovanie agarozy dlia izoliatsii belkov virusa grippa, sokhranivshikh vysokuiu immunogennost'.

A method of influenza virus separation in agarose was modified. The possibility of using agarose of the national make and Difco agar was established. RNP and M proteins were isolated. Highly active anti-M and anti-RNP sera were prepared which work well in the ELISA and RIA.

[Antigenic structure of the hemagglutinin of H1N1 influenza viruses studied by radioimmunological analysis]. / Izuchenie antigennoi struktury gemaggliutinina virusov grippa H1N1 metodom radioimmunologicheskogo analiza.

To elucidate the antigenic structure of influenza A (H1N1) viruses of different circulation periods (1947-1979) the criterion of participation of viruses of a constant test-group in competition for antibody from hyperimmune rabbit sera in radioimmunoassay (RIA) was used. The "set" of competing viruses varied with each immunospecific serum in relation to the immobilized strain for which the competitive capacity was studied. Each definite "set" of competing viruses was used as a marker of a certain type of antigenic determinant detected with a given test serum. Analysis of distribution of antigenic determinants and nonimmunogenic areas of hemagglutinin in the strains tested showed the drift nature of changes of the hemagglutinin antigenic properties. These changes may be grouped in 4 large antigenic regions, A, B, C, and D which appear to correspond to the "antigenic sites" revealed by Gerhard et al. by the monoclonal antibody procedure. Antigenic changes occur mainly in 3 of the above regions: A, B, and C in viruses of the first circulation period, and in B, C, and D in viruses of the second circulation period. Thus it has been shown that analysis of the antigenic structure of hemagglutinin by reciprocal radioimmunoassay of immunospecific sera to strains of the same subtype may be used as a tool for antigenic site mapping.

[Antigenic determinant study of the hemagglutinin in the composition of influenza viruses A subtype H1N1 by an indirect solid-phase radioimmunological analytical method]. / Izuchenie antigennykh determinant gemaggliutinina v sostave virusov grippa A podtipa H1N1 metodom nepriamogo tverdofazovogo radioimmunologicheskogo analiza.

A comparative study of antigenic determinants of influenza A virus, subtype H1N1, hemagglutinins isolated in 1947-1953 and in 1977-1979 was carried out. The competitive capacity of 8 virus strains for antibody of 4 hyperimmune antisera to A/Fm/1/47, A/Moscow/Pan/52, A/USSR/090/77, and A/Brazil/11/78 viruses was studied by solid-phase radioimmunoassay (SPRIA) in two modifications: in the homologous and heterologous systems. The analysis of competition in the heterologous system permits one to study isolated subpopulations of antibody homologous to viruses fixed on the solid phase. The combination of both modifications allows investigations of a wider spectrum of antibodies than those possible in the homologous system alone. The results of the study showed the antigenic determinants of hemagglutinin exposed on the surface of particles of different influenza A virus strains to differ in their capacity to stimulate antibody synthesis. The analysis of the time course of changes in the antigenic properties of hemagglutinin regions of similar structure in various viral strains may facilitate prognosing of evolution of virus strains of the same subtype.

[Analysis of heterogenous populations of antihemagglutinating antibodies in hyperimmune sera against influenza virus by indirect solid-phase radioimmunoassay]. / Analiz geterogennykh populiatsii antigemaggliutiniruiushchikh antitel v giperimmunnykh syvorotkakh k virusu grippa metodom nepriamogo tverdofazovogo radioimmunologicheskogo issledovaniia.

Populations of antihemagglutinating antibodies in hyperimmune rabbit sera to influenza A/PR8/34, A/Moscow/PAN/52, and A/Swine Iowa/15/31 viruses were examined by indirect competitive solid phase radioimmunoassay (SPRIA). Under conditions of competitive assay with immobilized virus homologous to the serum under test, not all subpopulations of cross-reacting antibodies in the sera are identified. Competition in the system of immobilized heterologous virus identifies a fuller spectrum of cross-reacting antibody. A composite analysis of the sera under both variants of competition showed each of the sera to contain a heterogenous population of antibodies interacting to various extents with determinants of a number of heterologous viruses classified, according to 1971 Nomenclature, as viruses with H0, H1, and Hsw1 hemagglutinin subtypes. The identification of cross-reacting antibodies permitted a conclusion on the existence of both antigenic determinants on the surface of hemagglutinin molecules of the viruses under study and an analysis of their variability. The pattern of changes of similar determinants in transition from viruses of one subtype to viruses of another subtype is characteristic of the drift type.

[Use of indirect solid-phase radioimmunological analysis for studying the antigenic properties of influenza virus]. / Primenenie nepriamogo tverdofaznogo radioimmunologicheskogo analiza dlia izucheniia antigennykh svoistv virusa grippa.

A method of indirect radioimmunoassay (RIA) for investigation of influenza virus antigenic properties and serum titrations was developed. The method is based on the detection of immobilized specific antigen-antibody complexes using 125I-labeled antispecies IgG. Antigen immobilization is done on the surface of polychlorvynil plate wells at alkaline pH, 37 degrees C for 2 hours. As compared with RIA in solution, the solid-phase RIA is a rapid method, the entire reaction taking 5 hours. The method is highly sensitive (dozen ng), reproducible, and economic. The latter property is important for screening of paired sera during epidemiological surveys of large groups of human population, since the small amount of the blood required may be collected from a finger and not from a vein of the patient. Experiments on competitive inhibition of antigen-antibody reaction done by the solid phase RIA permit quantitative evaluation of antigenic relationships among different influenza virus strains.