[Expression of hepatitis A virus procapsids in the insect cells infected by recombinant baculovirus].

The recombinant baculocvirus containing genome P1-2A-P3 of hepatitis A virus (HAV) was constructed and used for infecting the Sf9 insect cells. It was demonstrated that the deletion of 2BC from HAV polyprotein and the insertion of a new 3C protease cleavage site between P1-2A and P3 did not interfere with the processing of polyprotein or with forming the 70S-procapsids. The identity of the protein contents as well as of morphological and antigen characteristics, obtained in Sf9-cells, to HAV empty capsids, which take shape in the infected mammal cells, proves that it is possible to use them in making the vaccine and diagnostic preparations.

[Synthesis and immunochemical properties of oligopeptides--fragments of capsid proteins of the hepatitis A virus].

The hepatitis A virus (HAV) capsid protein VP1, VP2 and VP3 are exposed at the virion surface and should therefore contain antigenic determinants. Algorithms for hydrophilicity, antigenicity and flexibility were used to predict probable antigenic sites. Synthesis of 7- to 23-membered overlapping peptides from seven sites, viz.

[A comparative study of the sensitivity and specific activity of an immunoenzyme test system for determining class-M antibodies to the hepatitis A virus].

The diagnostic value of the first experimental production batches of assay kit "DIAGN-A-HEP", produced at the Institute of Poliomyelitis and Viral Encephalitides (USSR Acad. Med. Sci.

[The immunogenicity of a cultured inactivated hepatitis A vaccine].

A trial of inactivated hepatitis A viral vaccine of heteroploid cell culture origin is described. The vaccine preparation was tested in guinea pigs and tamarins. The animals were immunized intramuscularly four or three times, respectively.

[The antigenic properties of hepatitis A virus particles possessing different physicochemical characteristics].

A modified enzyme immunoassay based on adsorption of antihepatitis A virus (HAV) IgG-HRPO conjugate and monoclonal antibodies to HAV were used to investigate antigenic differences between mature HAV virions and subviral particles with different buoyant densities in CsCl produced in HAV-infected cells. The mature virions (1.34 g/cm3) appeared to have common antigenic determinants with subviral particles (1.

[The synthetic peptide 62-75 VP3 of the hepatitis A virus induces virus-binding antibodies].

Peptide (P6) representing amino acids 62-75 of HAV capsid protein VP3 was synthesized. Pure P6, octamer form of P6, and P6 conjugated to KLH were injected into rabbits. The sera against these preparations reacted with denaturized VP3 in immunoblotting tests; however, only anti-P6-KLH serum was capable of binding the native HAV.

[Mapping of the structural proteins of the hepatitis A virus].

The Western blot procedure with highly specific antipeptide antibody was applied to identify the electrophoretic mobility of hepatitis A virus capsid proteins. Polypeptides with molecular weights of 33, 29 and 27 kDa proved to be VP1, VP2, and VP3 proteins as they reacted with sera generated to VP1 recombinant protein and to synthetic oligopeptides 42-62 VP2 and 62-75 VP3, respectively.

[The results of serological research to determine hepatitis A and B markers in the blood sera of the population of the Republic of Guinea].

The results of examinations of sera from apparently normal urban and rural residents of the Guinea Republic (GR) for markers of viral hepatitis A (anti-HAV) and B (HBsAg) are presented. The number of HBsAg-positive subjects was 16 +/- 1% (1199 serum specimens were examined by direct enzyme immunoassay, EIA, and HI test), the rate of HBsAg findings in sera from children (less than 16 years) and adults (greater than or equal to 16) did not differ significantly (p less than 0.05).

[A trial of a cultured inactivated vaccine against hepatitis A on Saguinus mystax tamarins].

An experimental batch of inactivated hepatitis A vaccine was prepared using hepatitis A virus (HAV), HAS-15 strain, adapted to cell culture and purified by ultracentrifugation. The vaccine was tested in tamarins immunized intramuscularly three times one month apart. Three tamarins received a vaccine preparation containing 10 ng of immunogen each, three--100 ng each, and three animals were used as controls.

[A highly sensitive method of detecting the structural proteins of hepatitis A virus].

A modified technique of protein staining with silver nitrate was employed in electrophoretic analysis of hepatitis A virus structural proteins. The modifications of the original technique, i.e.

[Detection of hepatitis A virus RNA by molecular hybridization].

Hepatitis A virus (HAV) was propagated in continuous rhesus monkey embryo kidney cells (FRhK-4 line). HAV RNA extracted with phenol from purified HAV pretreated with proteinase K was used for molecular cloning experiments. Two radioactive plasmids, pHAV-23 and pHAV-5p, containing HAV cDNA fragments complementary to structural and nonstructural parts of HAV genome, respectively, were found to be useful for discrimination between mature virions and subviral structures.

[Trial of a Soviet diagnostic kit for determining class M immunoglobulins to the hepatitis A virus by immunoenzyme analysis (an anti-HAV IgM test system)].

The authors have studied the effectiveness of the first Soviet test system for the diagnosis of hepatitis A by means of the enzyme immunoassay (Diagn-A-Hep), developed at the Institute of Poliomyelitis and Viral Encephalitides, Moscow, under the conditions of different epidemic situations. In the process of this trial the high specificity and sensitivity of this test system, established earlier in the certification and commission trials, have been confirmed. Diagn-A-Hep has proved to be highly effective in the diagnosis of acute forms of hepatitis A and permitted its detection in patients during the incubation period, as well as in patients with anicteric and asymptomatic subclinical forms.

[Development of a Soviet diagnostic kit for determining class M immunoglobulins to the hepatitis A virus by immunoenzyme analysis (a test system for anti-HAV IgM)].

A new test system Diagn-A-Hep for the laboratory diagnosis of hepatitis A (HA) by means of the enzyme immunoassay has been developed at the Institute of Poliomyelitis and Viral Encephalitides (Moscow). The sensitivity and specificity of the newly developed test system have proved to be similar to those of the well-known commercial diagnostic system HAVAB manufactured by Abbott Laboratories (USA). Diagn-A-Hep permits the diagnosis of HA with 96-100% effectiveness both in patients with the acute form of the disease and in patients with its anicteric or inapparent forms.

[Hepatitis A in Macaca fascicularis and M. arctoides infected by the Java monkey-55 strain of hepatitis A virus].

The results are presented dealing with experimental inoculation of M. fascicularis and M. arctoides with a strain of hepatitis A virus (HAV), YaM-55, isolated from a M.

[Adaptation of hepatitis A virus strain (JaM-55) originally pathogenic for monkeys to a cell culture].

The results of adaptation of hepatitis A viral strain JaM-55 to the culture of embryo kidney cells FRhk-4 from macaque Rhesus are presented. The viral strain was isolated from a M. fascicularis suffering from spontaneous hepatitis.

[Accumulation of the infectious virus and the viral antigen during the multiplication of the hepatitis A virus in an embryonic kidney cell culture of the rhesus macaque (FRhK-4)].

Growth characteristics of the HAS-15 strain of human hepatitis A virus (HAV) in rhesus monkey foetal kidney cell line (FRhK-4) are described. The conditions optimal for the accumulation of infectious HAV and viral antigen (HAAg) in the infected cells and tissue culture fluids were studied. The production of infectious HAV occurred in the first stage while in the second stage predominantly HAAg was accumulating intracellularly.

[Properties of hepatitis A virus particles produced during infection in vitro].

Four types of virus-specific particles with different sedimentation coefficients and buoyant densities in CsCl were shown to be accumulated in hepatitis A virus (strain HAS-15) infected fetal rhesus monkey kidney cells (FRhK-4 line). Unlike the mature virions (155S, 1.34 g/cm3), cell-associated isosedimenting 92 S-particles (buoyant densities of 1.

[Dynamics of the accumulation of virus particles with different physico-chemical properties in FRhK-4 cells infected with hepatitis A virus].

The propagation time-course of hepatitis A virus (HAV, strain HAS-15) in continuous culture of the foetal rhesus monkey kidney cells (FRhK-4) was investigated. The HAV infectivity and viral RNA content in the infected cells reached the maximal level 5-8 days after infection, while accumulation of hepatitis A antigen (HAAg) continued for 2-3 weeks more. Viral particles with the densities 1.

[Association of the hepatitis A virus with the membranes of infected cells].

"Light" viral antigen (HAAg) with buoyant density 1.20 g/cm2 and sedimentation coefficient 92S are accumulated together with mature viral particles in Hepatitis A virus (HAV) infected FRhK-4 cells. This HAAg is localized predominantly in endoplasmic reticulum fraction of infected cells, while nature virions are localized in cytosol.

[Subunit immunogen of the tick-borne encephalitis virus. The immunological characteristics of glycoprotein V3 from 2 antigenic types of tick-borne encephalitis virus].

V3 glycoprotein isolated from virions of two antigenic types of TBE virus was found to be a valuable immunogen in experimental immunizations of rabbits and mice. The immune sera contained high titres of antibodies to TBE virus and other viruses of the TBE antigenic complex detectable in three serological tests. Species-, type-, and group-specific antibodies to TBE viruses were demonstrated.

[Subunit immunogen of the tick-borne encephalitis virus. The isolation of glycoprotein V3 from 2 types of the tick-borne encephalitis virus and a study of its amino acid composition].

An effective method for isolation of the membrane structural E protein, the so-called V3 glycoprotein, is described. Preliminary data of its amino acid composition have been obtained.

[Cloning and primary structure of DNA copies of genome fragments of the tick-borne encephalitis virus].

RNA of a flavivirus-tick-borne encephalitis virus (Far-East, type 1, strain Sofin) was subjected to reverse transcription and the DNA copy was transformed into double-stranded DNA by action of E. coli DNA-polymerase (Klenow's fragment) without primer. The hairpin structures were removed by S1 nuclease.