Persistent SV5 virus infection in continuous cell cultures.

A continuous line of guinea pig kidney cells (CGPK/H) and a continuous line of mouse fibroblasts (L/H) spontaneously infected with parainfluenza virus SV5 were found. These cultures showed no enhanced cell degeneration or symplast formation, nor was haemagglutinin accumulation or infectious virus demonstrated in them. However, regular reproduction of ribonucleoprotein (RNP) characteristic of parainfluenza viruses, morphologically complete virions and antigens producing antibody to SV5 virus were found in the cells. Focal haemadsorption neutralized by antiserum to SV5 virus was also demonstrated. The infection persisted in the cell populations for over 2 years (the observation period) under standard conditions of cell dispersion and subcultivation.

[Biological and genetic properties of a polyploid-forming mutant of the Venezuelan equine encephalomyelitis virus]. / Biologicheskie i geneticheskie svoistva mul'tiploidformiruiushchego mutanta virusa venesuél'skogo éntsefalomielita loshadei.

Some genetic and biological properties of the multiploid -forming mutant of Venezuelan equine encephalomyelitis virus as well as of standard and multiploid virions isolated from its population were analysed. The mutant steadily retained the capacity for formation of multiploid virions comprising up to 20% of the population both in passages in CEF culture and in the progeny of multiploid and standard virions. Owing to this, the concentration of multiploid virions in the population of this mutant remains at a constant level. Formation of multiploid virions compensates for the temperature-sensitive defect inherent in the standard virions which is associated with later stages of virus replication.

[Electron microscopy study of the midgut of ticks after experimental infection with Karshi virus]. / Elektronno-mikroskopicheskoe issledovanie sredeni kishki kleshchei posle éksperimental'nogo zarazheniia virusom Karshi.

The guts of H. asiaticum and H. anatolicum ticks infected with Karshi virus and incubated at 22 degrees and 37 degrees C were studied. Virus particles with morphological features of flaviviruses were found 5 days after infection in the cells of the gut of ticks incubated at 22 degrees C and within 24 hours postinfection in the gut cells of the ticks incubated at 37 degrees C. The possible effect of temperature on the rate of development and spread of the infectious process in the gut wall of the midgut of ticks of both species is discussed.

[Several methodologic problems in the control of cell cultures]. / Nekotorye metodicheskie voprosy kontrolia kletochnykh kul'tur

Some human and animal continuous cell lines as well as primary cell cultures were examined by karyological, electron microscopial, virological and molecular biological methods and also by the electrophoretic motility of glucose-6-phosphate dehydrogenase (G-6-PDG) in polyacrylamide gel. All human and animal continuous cell lines were shown to contain mycoplasma, 17-to contain intracytoplasmic particles of type A oncornaviruses, 5 -- type B oncornaviruses similar to Mason-Pfizer virus, 8 -- paramyxoviruses, 2 --oncornaviruses type C. A high molecular RNA with sedimentation constant 64--70 S was found in oncornaviruses isolated from cell cultures. Intracellular virus or subviral structures were detected by association of the reverse transcriptase activity with high molecular RNA. The presence in the cell cultures of marker chromosomes of HeLa cells, the absence in these cultures of Y chromosomes, the presence of the G-6-PDG enzyme with type A motility indicate the possibility of contamination of human continuous cell lines with HeLa cells.

[Identification of a hemadsorbing agent discovered in uninfected mouse L cell cultures and also the same cultures chronically infected with Sindbis virus]. / Identifikatsiia gemadsorbiruiushchego agenta, obnaruzhennogo v neinfitsirovannoi, a takzhe khronicheski infitsirovannoi virusom Sindbis perevivaemoi linii myshinykh kletok L

Electron microscope examinations of continuous lines of mouse L cells, both uninfected (L-init) and chronically infected with Sindbis virus (L-SV) revealed accumulations of ribonucleoprotein strands and virions corresponding by their parameters to paramyxoviruses in the cytoplasms of the cells. Further studies showed L-init and L-SV cell lines to have a manifest hemadsorption effect which could be completely inhibited by antiserum to parainfluenza SV5 virus. Immunofluorescence procedures detected intensive fluorescence in the cytoplasm of these cells which was observed only after treatment of the cells with antiserum to SV5 virus. In response to inoculation of cell homogenates of continuous L-init and L-SV cultures guinea pigs developed antihemagglutinating antibody to simian parainfluenza SV5 virus. On the basis of these results it may be assumed that virus-specific structures and viruses identical by their parameters to paramyxoviruses observed in electron microscope examinations of continuous mouse L-init and L-SV cells are simian parainfluenza SV5 virus.

[Electron microscopic study of chicken fibroblasts infected with the Tyuleniy virus (author's transl)]. / Elektronna-mikroskopicheskoe issledovanie kurinykh fibroblastov, zarazhennykh virusom Tiulenii

Uninfected and Tyuleniy virus-infected chick fibroblast cells were examined. Intracytoplasmic type A particles and immature type C particles of oncornavirus were found in uninfected cells. At 48 and 72 hours after inoculation of the cells with Tyuleniy virus a large number of mature C particles and virions of Tyuleniy virus were found in the cell cytoplasm. Possible relationships between A and C particles are discussed and a stimulating effect of Tyuleniy virus on mass maturation of C particles and their release from the cell is suggested.

[Electron microscopic studies of cell cultures of various origins]. / Elektronno-mikroskopicheskie issledovaniia kletok kul'tur tkanei razlichnogo proiskhozhdeniia

Thirty-four cell cultures of various origins were examined in the electron microscope. Mycoplasma were found in 31 cultures, A, C and D particles of oncornaviruses in 27 cultures, adenovirus in one culture and paramyxovirus in 8 cultures. Two cultures were found to be virus- and mycoplasma-free. A stringent control of cell cultures for the presence of viruses, mycoplasma or other microbiological agents is recommended.

[Morphological data on the reproductive characteristics of the LEIV-108A and LEIV-3306 Uz strains of the Baku virus in chick fibroblast cell culture]. / Morfologicheskie dannye o nekotorykh osobennostiakh razmnozheniia shatmmov LEIV-108A i LEIV-3306 Uz virusa Baku v kul'ture kletok kurinykh fibroblastov.

Electron microscopic examinations of chick fibroblast cells 24 hours after inoculation with LEIV-108A and LEIV-3306 Uz strains of Baku virus revealed the following: in the nuclei of the cells infected with the LEIV-108A strain fine granular matrices were found and virus particles were forming at the periphery of the nucleus; in the LEIV-3306Uz-infected cells virus particles were found budding from the plasma membrane of the cell.

[Transfection by integrated proviruses]. / Transfektsiia integrirovannymi provirusami.

Three lines of continuous mouse L cells were compared: one of them contained only its endogenic oncornavirus, another was contaminated with SV5 virus, and a third was obtained from the second line chronically infected with vesicular stomatitis virus. Experiments with transfection showed that it was possible to recover SV5 virus from the two former cultures and vesicular stomatitis virus from the latter.

[Study of the morphological aspects of Okhotskii virus replication in a chick fibroblast culture]. / Izuchenie morfologicheskikh aspektov replikatsii virusa Okhotskii v kul'ture kurinykh fibroblastov.

Electron microscopic studies of chick embryo fibroblast cells 24 hours after infection with Okhotsky virus revealed changes typical orbivirus infection in the cytoplasm and the nuclei of the cells. The nuclei of the infected cells contained fine-granular matrices with forming virus particles and tubular structures. The cell cytoplasm also contained tubular structures, crystal arrays, fine-granular matrices and virus particles 50-60 nm in diameter.

[Interaction of Sindbis virus with a culture of cells producing oncornavirus]. / Vzaimodeistvie virusa Sindbis s kul'turoi kletok,produtsiruiushchei onkornavirus.

Electron microscopy and biophysical methods were used for examinations of primarily trypsinized chick fibroblast cell culture spontaneously producing C-type oncornavirus at 1, 6, and 24 hours after inoculation with Sindbis virus. During the first 6 hours rapid maturation and release of oncornavirus from cells were observed. At later intervals oncornavirus production was inhibited. It is assumed that in the system under study, biosynthesis of oncornavirus and Sindbis virus occur separately.

[Multiploid virions of the Venezuelan equine encephalomyelitis virus. Isolation and properties]. / Mul'tiploidnye viriony virusa venesuél'skogo éntsefalomielita loshadei. Vydelenie i svoistva.

Multiploid virions present in the population of multiploid-forming mutant of Venezuelan equine encephalomyelitis (VEE) virus were isolated from preparations of purified and concentrated virus by methods of zonal centrifugation in glycerin density gradient or gel filtration through biogel A-150 m. The portion of multiploid particles in such preparations reached 70%-90%. The isolated multiploid virions retained their morphology, infectivity and hemagglutinating activity. The multiploid particles were found to differ from standard virions in the sedimentation rate and buoyant density.

[Finding of the herpes simplex virus by electron microscopic study of the biopsy from a cervical cancer patient]. / Obnaruzhenie virusa obychnogo gerpesa pri élektronno-mikroskopicheskom issledovanii bioptata bol'noi rakom sheiki matki.

The question of a possible etiological role of the family of herpes viruses in generation of human malignancies is discussed. The detection of herpes simplex virus in human tumor by electron microscopic examination of a biopsy sample from a cervical carcinoma patient is another proof of herpes virus association with human malignant neoplasias.

[Morphological study of a mixed alphavirus infection]. / Morfologicheskoe izuchenie smeshannoi infektsii al'favirusami.

In combined paired cultivation of 8 Venezuelan equine encephalomyelitis virus, multiploid virions formed in 17.8% of cases. Five clones with this effect were used in mixed infections with clones of Semliki Forest and Sindbis viruses. In these infections changes in virions of the virus progeny were observed in 20% and 16.6%, respectively. Mixed cultivation of pairs of Sindbis and Semliki Forest viruses resulted in formation of multiploid virions in 42.8%. Besides, in two mixed populations formed upon combined multiplication of the latter viruses virions of unusual shapes were found: rounded, oval, elongated, and triangular designated as polymorphic.

[Use of continuous human lymphoblastoid cell lines (T- and B-origin) to produce persistent tick-borne encephalitis virus and Venezuelan equine encephalomyelitis virus infections]. / Ispol'zovanie perevivaemykh limfoblastoidnykh linii kletok cheloveka (T- i B-proiskhozhdeniia) dlia polucheniia persistentnoi infektsii virusa kleshchegogo éntsefalita i virusa venesuél'skogo éntsefalomielita loshadei.

Persistent infection with tick-borne encephalitis virus (TBE) was established in experimentally infected continuous lymphoblastoid human cell lines Raji, L-101 (of B-origin) and 1387 (T-origin) and with Venezuelan equine encephalomyelitis (VEE) virus in Raji and 1387 lines. The persistently infected lines produced infectious virus, the cells showed specific fluorescence in immunofluorescent tests, and electron microscopic examinations revealed TBE and VEE virions in sections.

[Abortive influenza virus infection in Ehrlich ascitic carcinoma cells. Properties of virus particles and intracellular ribonucleoproteins]. / Abortivnaia infektsiia virusa grippa v kletkakh astsitnogo raka Erlikha. Svoistva virusnykh chastits i vnutrikletochnykh ribonukleoproteidov.

Ehrlich ascitic carcinoma cells infected with influenza virus, WSN strain, produced noninfectious virus particles differing by some properties from standard virions formed in chick embryo. The ascitic particles were unusually fragile and lost hemagglutinins during purification and storage. They were found in larger or smaller aggregates. In the electron microscope they appeared as spikeless particles of heterogeneous size. Polyacrylamide gel electrophoretic analysis of polypeptides revealed markedly decreased contents of hemagglutinins and M-protein. It is suggested that the decreased amount of M-protein results in the fragility of ascitic virus particles and loss of hemagglutinins which, in its turn, leads to the loss of infectivity. Ribonucleoproteins (RNP) synthesized in the cytoplasm and nuclei of Ehrlich ascitic carcinoma cells differed in their biophysical properties from RNP formed in the permissive system (chick fibroblast culture). They sedimented slower than RNP from chick fibroblasts, and their buoyant density was 1.37--1.40 g/ml instead of 1.34 g/ml, i. e. the density typical of influenza virus nucleocapsid.

[Virus isolated in the human blood leukocyte culture and its interaction with hepatitis C and G viruses]. / Virus, vydelennyi na kul'ture leikotsitov krovi cheloveka, i ego vzaimootnoshenie s virusami gepatitov C i G.

Electrone-microscopic investigations are indicative of that the cultures of healthy donors, stimulated by phytohemagglutinin (PHA), can be successfully used to study the etiology of parenterally transmitted hepatitis. An electronic-microscopic study of a virus, isolated from the blood serum of a patient with hepatitis on the basis of the PHA-stimulated human leukocyte cultures and named a hepatitis leukocytic virus (HLV), enabled, by using the negative contrasting method, to detect viral particles of the hexagonal shape, sized 50-65 nm, with a coating divided by a 4-5 nm light space. Therefore, the HLV was described as belonging to the Flaviviridae family. RNA of the C hepatitis virus was detected in the K HLV strain stored, for 24 years, at the Museum of the Viruses Research Institute, Russian Academy of Medical Sciences, in a lyophilizated bed at -5 degrees C, however, an attempt to genotype the RNA failed. No RNA donor leukocytes were found in the materials of further passing of HLV by using the PHA-stimulated cultures, which can be explained by an inactivation of HLV at storage. No RNA of the C hepatitis virus was found in the above materials either, however, in 1999, DNA of the TT virus was detected at passing the strain, which indicates that the virus is widely spread in the population of healthy donors, whose lymphocytes are used preparing the blood leukocyte cultures.

[Morphological analysis of a cell system, infected with different strains of the human immunodeficiency virus]. / Morfologicheskii analiz kletochnykh sistem, infitsirovannykh razlichnymi shtammami virusa immunodefitsita cheloveka.

Cell systems infected with 63 strains of types 1 and 2 HIV virus (HIV-1 and HIV-2) were examined under electron microscope. HIV virions were most frequently detected near the cell membrane or budding from it. In the cytoplasm HIV occurred only in vacuole-like formations. Accumulations of mature virions were seen in the cell-to-cell space. Mature particles of HIV-1 and HIV-2 differed by their morphology from oncoviral C particles and were similar rater to the Visna/Medi type Lentiviruses. Morphological analysis of HIV strains isolated in Russia demonstrated their similarity to be foreign HIV strains.

[Experimental infection of ixodid ticks with Karshi virus]. / Eksperimental'noe zarazhenie iksodovykh kleshchei virusom Karshi.

The ixodid ticks Hyalomma asiaticum, H. anatolicum, Dermacentor niveus were infected experimentally with Karsha virus. The virus replication has been proved to occur in the tick's organism. The titre of the virus grows gradually in infected ticks. Entering the tick's gut during its feeding virus particles penetrate into the gut walls where primary multiplication and accumulation of the virus take place.

[Transformational activity of the oncornaviruses isolated from RH and Hep-2 cell lines]. / O transformiruiushchei aktivnosti onkornavirusov, vydelennykh iz kletochnykh linii RH i Hep-2.

Oncornaviruses isolated from transplantable cell cultures Hep-2 and RH were used for inoculating primary tripsinized cell cultures of human foetal kidney (HFK) and human embryonic fibroblasts (HEF). In all 15 cases no transformation of HEF cells was noted. In inoculation of HFK with oncornaviruses isolated from RH cell culture in 2 of 16 cases there were obtained transformed cell cultures: HFK+VRH and HFK+VRH Mc) occurred twice as fast. The transformed cell cultures have gone through 15-23 passages and were characterized by a high mitotic activity, production of oncornaviruses, type A and B, and absence of contact inhibition, a capacity for multistratum three-dimensional growth, the modal number of chromosomes 64 and a mixed type AB of electrophoretic mobility of glucoso-6-phosphate dehydrogenase.