[Seroepidemiological characterization of virus hepatitis in the Republic of Armenia].

The survey of the population immunological structure with respect to parenteral hepatitis showed awide circulation of hepatitis B (HB) and hepatitis C (HC) viruses among the adult population of Armenia. During the 5 year period of observation the number of persons having antibodies to HC virus increased 2.7-fold. High occurrence of antibodies to HBsAg of HB virus among the healthy population in 2002 (12.0%) in comparison with 1997 (5.4%) reflected a decreased infection rate with HB virus as well. Antibodies to hepatitis A (HA) virus were isolated, on the average, in 64 % of persons. Simultaneously with a decrease in the proportion of HA cases an increased number of HC patients was registered. No circulation of hepatitis E virus was detected. A high percentage of hepatitis cases of mixed etiology was established, as well as an increased number of combined parenteral hepatitis cases was registered (57.1%).

[Experiment in infecting the green monkey Cercopithecus aethiops with a leukocyte virus isolated in hepatitis A]. / Opyt zarazheniia zelenykh martyshek Cercopithecus aethiops leikotsitarnym virusom, vydelennym pri gepatite A.

The virus isolated in hepatitis A had been previously shown to passage in primary phytohemagglutinin-stimulated leukocyte cultures. The virus designated as leukocyte hepatitis virus (LHV) causes chromosome aberrations in the infected cultures. Some physico-chemical properties of LHV and its capacity for reproduction in other cell systems were studied. In serological surveys of patients and in studies of cellular immunity reactions of them LHV was found in cases of hepatitis. The possibility of producing a laboratory model of hepatitis in green monkeys, morphological reaction to inoculation with LHV, as well as the presence of specific antigen in the inoculated animals by immunofluorescence test using rabbit immune serum to LHV and FITC-labelled gamma globulins from hepatitis A convalescents were investigated. LHV antigen was found in the lymph nodes, spleen and liver. Active morphological reaction of lymph nodes and spleen was observed 30 days after inoculation of monkeys. The results indicate that in green monkeys LHV possesses marked reticulotropic properties without producing clinical hepatitis, therefore African grivet monkeys (Cercopithecus aethiops), apparently, cannot be used as experimental models for LHV studies in vivo.

[Chronic tick-bone encephalitis virus infection in continuous human lymphocyte lines studied by molecular hybridization]. / Izuchenie khronicheskoi infektsii virusa kleschevogo éntsefalita v perevivaemykh liniiakh limfotsitov cheloveka metodom molekuliarnoi gibridizatsii.

Chronic infection with tick-borne encephalitis virus (Sophyin strain) has been established in continuous lines of human lymphocytes (of T- and B-origin). In 3 lines under study, the cultured virus at the level of the 15th passage had a titre of 7.22-8.02 lg LD50ml, the virus-specific antigen was determined in the cytoplasm of 80% of T-lymphocytes (line 1387). The method of RNA-DNA hybridization demonstrated the presence of virus-specific sequences in DNA preparations from infected cells in amounts not exceeding 1 copy of virus genome per 10-25 cells.

[Modeling chronic infection in a T-lymphocyte-Venezuelan equine encephalomyelitis virus system]. / Modelirovanie khronicheskoi infektsii v sisteme T-limfotsit--virus venesuél'skogo éntsefalomielita loshadei.

A model of chronic infection in the system of T-lymphocyte--VEE virus was made. Production of infectious VEE (up to 6.0 lg PFU/ml), tissue culture interferon levels (less than 10 units/ml), accumulation of virus-specific antigen in chronically infected continuous human T-lymphocytes (78%) were studied. The presence of virus-specific sequence in DNA from infected cells was studied by the method of molecular hybridization and found not to exceed one DNA replica of virus genome per three cells of chronically infected T-lymphocyte culture.

[Alphavirus reproduction in cultures of transplantable human lymphoblastoid cells during persistent infections]. / Reproduktsiia al'favirusov v kul'turakh perevivaemykh limfoblastoidnykh kletok cheloveka pri persistiruiushchei infektsii.

The results of virological investigations of alphavirus persistence in human B-cell lines Raji and L-101 are presented. The formation of persisting infection was shown to depend both on the cell line and on the virus type. Productive persistent infection of Raji cells with Venezuelan equine encephalitis virus was followed for 11 months. The presence of the virus was confirmed by electron microscopic and immunofluorescent examinations. Infectious virus production varied from 0.001 to dozens PFU/cell, and the content of viable cells from 100,000 to 300,000 in 1 ml of the culture fluid. Virus infectivity in the culture medium varied within the range of 5-7 lg PFU/ml. Human lymphoblastoid cells Raji persistently infected with Venezuelan equine encephalitis virus were examined cytologically, karyologically, and electron microscopically. The long-term presence of the virus resulted in profound alterations in the cell population. Morphology of the cells and processes of division were changed, the mitotic index decreased, the rate of 3H-thymidine incorporation into cellular DNA increased. The mechanisms of persistence are discussed.

[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.