Expression of active secreted forms of human amyloid beta-protein precursor by recombinant baculovirus-infected insect cells.

Three alternatively spliced forms of the amyloid precursor protein (APP), APP-695, APP-751, and APP-770, were expressed in the baculovirus expression vector system. The recombinant proteins were secreted into the culture medium by infected insect cells, and APP molecules were detected in insect cells and medium 2 days after infection with the recombinant APP-baculoviruses. A partial sequence of the NH2 terminus of the secreted protein revealed identity with the native secreted protein and showed that the signal peptide was recognized and properly cleaved in insect cells. Purified secreted recombinant APP-751 comigrated with protease nexin 2 purified from platelets and fibroblasts. A 15-kDa COOH-terminal fragment of APP was also detected in cells infected with recombinant baculoviruses, suggesting that recombinant APP proteins were cleaved at the COOH-terminal end like native APP protein. Recombinant APP-751 and APP-770 formed complexes with epidermal growth factor-binding protein, whereas APP-695 did not. In addition, recombinant APP-751 and APP-770 inhibited trypsin and chymotrypsin activity, whereas APP-695 did not. Growth of a human fibroblast cell line, A-1, that required APP for complete growth, was restored upon addition of secreted recombinant APP-695 or APP-751. Thus, the appropriately sized, secreted recombinant APP proteins produced in this expression system are biologically active.

[The results of a controlled field trial of a dried erythrocytic immunoglobulin diagnostic agent for detecting the hepatitis A virus antigen]. / Rezul'taty polevogo kontroliruemogo ispytaniia diagnostikuma éritrotsitarnogo immunoglobulinovogo sukhogo dlia vyiavleniia antigena virusa gepatitia A.

The results of the controlled field trial of lyophilized erythrocytic immunoglobulin diagnosticum for the detection of hepatitis A virus antigen in the urine and feces of patients are presented. This diagnosticum was used for the study of urine and fecal samples from 225 patients (of these, 176 had hepatitis A) and 54 healthy persons in the passive hemagglutination (PHA) test. Their blood sera were studied in the PHA test (to detect HBsAg) and the radioimmunoassay (to detect anti-HAV IgM). The immunoglobulin diagnosticum under study was found to be nonspecific and faintly sensitive and, therefore, unsuitable for use in medical practice.

[The antigenic properties of hepatitis A virus particles possessing different physicochemical characteristics]. / Antigennye svoistva chastits virusa gepatita A, obladaiushchikh razlichnymi fiziko-khimicheskimi kharakteristikami.

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 (1.20, 1.27, and 1.30 g/cm3) and possess some additional determinants. Nevertheless, both subviral particles and mature virions induced antibodies capable of neutralizing HAV infectivity in tissue culture.

[The results of serological research to determine hepatitis A and B markers in the blood sera of the population of the Republic of Guinea]. / Rezul'taty serologicheskikh issledovanii po opredeleniiu markerov gepatitov A i B v syvorotakh krovi naseleniia Gvineiskoi Respubliki.

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). The rate of a HBsAg carrier state did not depend on sex and residence of the subjects under study (p less than 0.05). The detection rate of total (IgM + IgG) anti-HAV antibody was 67 +/- 2% (812 serum specimens were examined by a variant of EIA block). The detection rate and titres of anti-HAV in children were higher than in adults, and in urban residents higher than in rural subjects (p less than 0.05). The results of detection of HBsAg and total anti-HAV antibody in the sera of GR residents are close to those obtained in examinations of sera from the populations of countries bordering GR in Western Africa (Senegal, Mali, Liberia) and are typical of Africa as a whole.

[Virological and serological characteristics of outbreaks and sporadic cases of acute gastroenteritis]. / Virusologicheskaia i serologicheskaia kharakteristika vspyshek i sporadicheskikh sluchaev ostrogo gastroénterita.

Specimens from patients with gastroenteritis (GE) collected during outbreaks and from sporadic cases reported in the USSR in 1979-1984 were examined by electron microscopy (EM), enzyme immunoassay, rotavirus neutralization test in cell culture. All the winter-spring outbreaks and a considerable number (34.9%) of sporadic GE cases were caused by rotaviruses. The summer-autumn outbreaks were of non-rotavirus nature. In water-borne winter-spring outbreaks in adults, severe forms of GE with signs of dehydration were observed. Among infants, cases of virus-carrier state were detected. The rate of rotavirus detection by EM in winter-spring outbreaks depended on the time of specimen collection and decreased after 4 days from the onset of the disease. Apart from rotaviruses, adeno-, astro-, calici-, coronaviruses, and picornavirus-like particles were detected by EM in feces from GE patients.

[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)]. / Ispytanie otechestvennogo diagnosticheskogo komplekta dlia opredeleniia immunoglobulinov klassa M k virusu gepatita A immunofermentnym analizom (test-sistema na anti-VGA IgM).

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. Besides clinical diagnosis, the kit Diagn-A-Hep may be used in large-scale seroepidemiological surveys of the immune structure of the population, as well as in detection of HAV in different material under test.

[Dhori virus--a causative agent of human disease. 5 cases of laboratory infection]. / Virus Dkhori--vozbuditel' zabolevaniia cheloveka. Piat' sluchaev laboratornoi infektsii.

The materials presented in the paper are first indications of the pathogenicity of Dhori virus for man and prove the role of this agent in the occurrence of 5 cases of the disease in laboratory workers accidentally infected during the preparation of cultural agents. Clinically, Dhori infection was characterized by an acute course with marked general toxicity and a febrile period of 2 to 4 days. Two out of 5 patients had changes on the part of the nervous system of the type of encephalitic reaction predominantly with subcortical symptoms and mild involvement of the pyramidal system or in the form of encephalopolyradiculoneuritis with paresthesia and sensitivity disorders.

[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)]. / Razrabotka otechestvennogo diagnosticheskogo komplekta dlia opredeleniia immunoglobulinov klassa M k virusu gepatita A immunofermentnym analizom (test-sistema na anti-VGA 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. This system is simple and convenient, it may be employed in inadequately equipped laboratories or even under field conditions. The rules for the selection of immunobiological preparations to be included in the test system have been worked out.

[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)]. / Nakoplenie infektsionnogo virusa i virusnogo antigena pri razmnozhenii virusa gepatita A v kul'ture kletok pochki émbriona makaki rezusa (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. Serological properties of the cultivated HAV proved to be very similar to those of the HAV occurring in hepatitis A patients.

[Virus--the causative agent of hemorrhagic fever with renal syndrome--a new representative of the family Bunyaviridae]. / Virus--vozbuditel' gemorragicheskoi likhoradki s pochechnym sindromom--novyi predstavitel' semeistva Bunyaviridae.

Physicochemical characteristics (sedimentation coefficient, buoyant density of particles, as well as ribonuclein of these particles) and morphology of the causative agent of hemorrhagic fever with renal syndrome were found to be similar to those of the other members of the Bunyaviridae family.

Immunosorbent assays for diagnosis of Crimean-Congo hemorrhagic fever (CCHF).

Utilization of direct and indirect enzyme-linked immunosorbent assay (ELISA) and solid-phase radioimmunoassay (SPRIA) for the diagnosis of Crimean-Congo hemorrhagic fever (CCHF) allows the detection of low amounts of infectious virus (2 log LD50) or inactivated antigen and antibody to CCHF within 5-6 hours. These methods were shown to be more sensitive, specific, rapid, and reproducible than the complement-fixation test, immunofluorescence, hemagglutination, or radial diffusion in gel. The experimental design of ELISA and SPRIA developed for CCHF may be used successfully for the detection of the other members of the Bunyaviridae family.

Physicochemical characteristics, morphology and morphogenesis of virions of the causative agent of Crimean hemorrhagic fever.

Similar physicochemical characteristics were found with strains of Crimean hemorrhagic fever (CHF) and Congo viruses. The particle size, sedimentation coefficient, buoyant density, weight of the particles as well as morphology and morphogenesis of these viruses were similar to those of other members of the Bunyaviridae family. Data are presented on reproduction of CHF virus in cell cultures and on the inner structure of its virion.

Morphology and morphogenesis of Crimean hemorrhagic fever virus.

Morphological characteristics of Crimean Hemorrhagic Fever Virus indicate that it is closely related to the Bunyaviridae family. However, there are some features (e.g. formation of crystal-like patterns in infected cells) demonstrating differences to the other known Bunyaviridae.