Extensive C-terminal deletion in human immunodeficiency virus type 1 Env glycoprotein arising after long-term culture of chronically infected cells.

Human immunodeficiency virus type 1 (HIV-1) chronically infected (CI) cell lines were established from HIV-1HIB/LAI-infected MT-4 cells that survived acute infection. The HIV env gene expressed in the two long-term cultured cell lines differed from that of the lines cultured for shorter periods, by coding for a glycoprotein gp 160 that had the C terminus deleted. One long-term cultured cell line, CI-17, was studied in detail.

[Pathological cleavage of human immunodeficiency virus gp160 protein in infected cells as a probable factor for infection becoming chronic].

The synthesis of HIV-1 (IIIb isolate) structural protein in chronically (CI) and acutely infected (AI) MT4 cells was studied. During long-term cultivation the CI system was characterized by high involvement of the cells into infection (up to 100%), high level of virus-specific protein synthesis, moderate virus yield, but absence of any virus-induced cytopathic effects and normal growth potential of infected cells. AI cells demonstrated a similar level of synthesis of virus specific proteins, higher virus yield, and rapid progression of cytopathicity followed by total cell death.

[Group- and type-specific antibodies to the gag-gene protein p26 of the human immunodeficiency virus immunological type 2 in infected patients].

The immunoreactivity of serum samples from HIV-2 infected persons was studied by radioimmunoprecipitation assay (RIPA) in homo- and heterotypic variants. In homotypic RIPA all sera studied have precipitated the viral glycoprotein with the high molecular weight, gp170. Some samples were active for gag-gene products, p57 and p26 in homotypic RIPA.

[A radioimmunoprecipitation method in the serodiagnosis of HIV infection: the development of the optimal conditions for its performance and the evaluation of the possibilities for its use].

The optimum conditions for using the method of radioimmunoprecipitation (RIP) for the detection of human immunodeficiency virus (HIV) in serum samples have been established. Out of several available cell lines persistently infected with HIV, specially selected line 17 has been chosen. The characteristic feature of this is the high and stable (under the conditions of prolonged cultivation) accumulation of virus-specific proteins in infected cells.

Consolidation of intramolecular disulfide bonds in influenza virus hemagglutinin as an element of intracellular maturation.

Electrophoretic behavior of influenza virus hemagglutinin during SDS electrophoresis in polyacrylamide gel is critically dependent on the life time in the infected cells and also on the conditions of sample preparation and analysis. During electrophoresis of total cell lysate proteins under nonreducing conditions the short-labeled hemagglutinin is detected as multiple bands, electrophoretic mobility of most of them being lower than that of hemagglutinin of viral particles. This heterogeneity failed to be detected during electrophoresis under reducing conditions which is indicative of the differences in the number or direction of intramolecular disulfide bonds between short-labeled and mature hemagglutinin molecules.

[Masking of HIV antigen by specific antibodies in a model experiment].

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.

[A comparison of the spectra of antibodies to individual proteins of the human immunodeficiency virus in seropositive sera collected in the territories of the USSR and England].

Antibody spectra to individual proteins of human immunodeficiency virus (HIV) in 74 seropositive serum samples collected in the USSR and 65 serum samples collected in Britain were studied by immunoblotting techniques. Most of the sera belonged to clinically healthy persons, some of the sera collected in Britain contained specific IgM antibodies. The results were evaluated qualitatively and quantitatively.

Breaking and rejoining of disulfide bonds in external glycoproteins of influenza virus.

The treatment of influenza virus with increasing concentrations of mercaptoethanol led to a progressive inhibition of hemagglutinating activity and infectivity and to gradual changes of electrophoretic behavior of virus glycoproteins under nonreducing conditions. These phenomena are most likely the result of consecutive destruction of disulfide bonds in the proteins. So, different disulfide bonds in glycoproteins of native viral particles differ in their sensitivity to the reductant.

Controlled organization of multimolecular complexes of enveloped virus glycoproteins: study of immunogenicity.

Some technological and immunological problems facing the preparation of subunit viral vaccines are discussed. Solubilization of enveloped virus glycoproteins with various detergents has been studied. It has been demonstrated that a novel non-ionic detergent, MESK, can be used to prepare the glycoproteins of enveloped viruses in defined supramolecular forms: monomers, micelles, liposomes and multimeric complexes.

[The low frequency of false positive results in the serological detection of infectivity with the human immunodeficiency virus in collectives of healthy young people].

Among 1002 foreign students examined in Odessa 11 subjects with antibody to HIV, i.e. infected with HIV, were detected.

[Preparative isolation of purified antigens of the herpes simplex virus type I and a study of their immunogenic properties].

The HSV-I-containing material prepared in chick embryo fibroblast cultures was concentrated on nuclear filters followed by chromatography on a column with large-pore silica. The MESK detergent was used for isolation of glycoproteins. The glycoprotein preparation was highly immunogenic in experimental animals.

[Conditions for efficient antibody binding with proteins of the human immunodeficiency virus studied by immunoblotting].

The authors have investigated the antibody binding with individual HIV protein by "western" blotting method. The optimal condition for binding was incubation of nitrocellulose strips at 37 degrees C for 2 hrs followed by incubation at 4 degrees C overnight. Differences in the serologic activities of a number of sera in "western" blotting were shown by using two different antigens.

[Use of an immune blotting method (western) for studying viral antigens and for detecting antibodies to viral proteins].

The technique of the procedure and the results of the use of immune ("western") blotting method for studies on viral antigens and detection of antibodies to individual proteins of viral particles are described. The possibility of detection and study of individual viral antigens in the whole plasma of patients or carriers is demonstrated by the example of HBs antigen of human hepatitis B virus. The method of immune blotting was used for screening of human sera for the detection of antibodies to the AIDS virus proteins.

[Isolation of polymeric glycoprotein complexes of enveloped viruses using the Quill A glycoside and a study of their immunogenic activity].

Specific multimer complexes of glycoproteins of enveloped viruses were prepared by treatment of suspensions of purified concentrated virus with a non-ionic detergent MECK mixed with 0.2% glycoside Quil A. Mixed complexes of glycoproteins with glycoside Quil A were formed upon removal of the detergent from the mixture of solubilized glycoproteins and glycoside Quil A.

[Disulfide maturation of the glycoproteins of influenza virus hemagglutinin and neuraminidase in infected cells].

Fractionation by polyacrylamide gel electrophoresis (PAGE) demonstrated that in the infected cells the newly synthesized influenza virus glycoproteins, hemagglutinin (HA) and neuraminidase (NA), differ from mature proteins of virus particles. After some time of life in the cells the differences are levelled. Since this phenomenon was demonstrable only in an analysis under the conditions favourable for the retention of disulphide bonds, it was designated as "disulphide maturation" of glycoproteins.

[Biological consequences of breaks and reunions of disulfide bonds in influenza virus proteins].

Consequences of chemical breakage of native disulphide bonds in influenza virus neuraminidase and hemagglutinin glycoproteins induced by mercaptoethanol treatment were studied. Under conditions of blocked reoxidation of thiol groups, this treatment led to significant inhibition of hemagglutinating activity and infectivity of virus particles, and to a lesser inhibition of neuraminidase activity, as well as to promotion of endogenous proteolytic activity. Analysis of virus particles proteins by polyacrylamide gel electrophoresis indicated association of these biological effects with breakage of disulphide bridges, mainly in hemagglutinin glycoproteins.

[Expert diagnosis of infectivity with the AIDS virus using immune blotting: the development of a system and assessment of its parameters].

A system for serodiagnosis of infection with AIDS viruses by means of immune ("western") blotting has been developed. The system has been found to be highly sensitive and suitable for expert serodiagnosis of AIDS disease and infection with human AIDS viruses.

[Chromatographic behavior of the hepatitis B virus surface antigen in donor plasma].

Behavior of HBsAg in adsorption chromatography of the antigen-containing plasma in a column with unmodified macropore silica was studied. Under the employed conditions of overlaying and elution, five maximum yields of plasma proper proteins from the column (peaks 1-5) were observed. HBsAg was determined mainly in the material of peaks 4 and 5 in which the dominating host protein was lipoprotein HDL.

[Inhibition of the infectivity of enveloped viruses while retaining the specific biological activity of the viral proteins].

A method of inactivation of enveloped viruses by treatment of virus-containing material with a nonionic detergent MESK was studied. Treatment with the detergent of allantoic or culture fluids containing influenza, parainfluenza, herpes simplex, and Venezuelan equine encephalomyelitis viruses was shown to result in significant (to 10 lg ID50) decrease of the infectivity of the viruses. At that, the specific biological activity of viral proteins: the hemagglutinating and neuraminidase activities in the case of influenza and parainfluenza viruses, and the hemagglutinating activity in the case of Venezuelan equine encephalomyelitis virus, remained unchanged.

[Binding of the surface antigen of the hepatitis B virus with antibodies studied with different denaturation exposures and with different analytical methods].

The effect of delipidizing agents and a reducing agent on the antigenicity of 20 nm particles of hepatitis B virus surface antigen (HBsAg) was studied. The antigenicity was determined from the capacity of binding with antibody in passive hemagglutination test (PHAT) and dot-blot immune binding (DBIB). Delipidation was found to lead to an apparent decrease of antigenicity caused by aggregation.

[Solubilization of glycoproteins from enveloped viruses by detergents].

The effects of some known ionic and nonionic detergents as well as that of a novel nonionic detergent MESK on various enveloped viruses were investigated. It was found that nonionic detergens (MESK, Triton X-100, octyl-beta-D-glucopyranoside) selectively solubilize glycoproteins of enveloped viruses. The most mild selective action is exerted by the nonionic detergent MESK.