[The study of immune structure of Astrakhan region population to West Nile virus in 1998 and 1999].

Immunostructure of the Astrakhan Region population to West Nile fever (WNF) was studied in the preepidemic period (1998) and after the outbreak (1999). Among the sera obtained in 1998, 63 (26.3%) were positive in neutralization reaction, 84 (27.

[Characteristics of humoral immunity to rubella virus in residents of Moscow in 1998-1999].

A total of 400 blood samples were collected from residents of Moscow in 1998-1999, 369 from adults aged mainly 19-31 years and from children aged 5-12 years. The mean incidence of antirubella antibody was 76.5%; the value varied in different age groups.

[Genetic analysis of West Nile fever virus, isolated in the south of the Russian plain (Volgograd and Astrakhan regions) in 1999].

Two strains of West Nile virus, Vlg 27889 and Ast 986, were isolated from the brain of a dead man and from the blood of a patient, respectively, during an outbreak of serous meningitis and meningoencephalitis in July-September, 1999, in the Volgograd and Astrakhan regions. Analysis of parts of genome of the strains cloned from cell culture by reverse transcription and polymerase chain reaction demonstrated their identity and appurtenance to group I West Nile viruses.

[Virus-like particles as a source for obtaining antigens for diagnosing rubella].

Rubella diagnostic agents for hemagglutination inhibition (HI) and enzyme immunoassay (EIA) based on rubella virus-like particles (RVLP) have been developed. Noninfectious RVLPs containing three structural E1, E2, and C proteins were expressed in transfected CHO24S cell culture. HI titer in culture medium was 1:256.

Isolation of two strains of West Nile virus during an outbreak in southern Russia, 1999.

From July to September 1999, a widespread outbreak of meningoencephalitis associated with West Nile virus (Flavivirus, Flaviviridae) occurred in southern Russia, with hundreds of cases and dozens of deaths. Two strains of West Nile virus isolated from patient serum and brain-tissue samples reacted in hemagglutination-inhibition and neutralization tests with patients' convalescent-phase sera and immune ascites fluid from other strains of West Nile virus.

[Isolation of the West Nile Fever virus from human patients during an epidemic outbreak in the Volgograd and Astrakhan regions].

Two strains of West Nile virus LEIV 27889 Vig and Ast 986 were isolated from the brain of a dead subject and from the blood of a patient, respectively, during an outbreak of serous meningitis and meningoencephalitis in July-September, 1999, in the Volgograd region, Krasnodar territory, and Astrakhan region. These strains reacted with convalescent sera in hemagglutination inhibition test, which proves their etiological role in this outbreak.

[Epidemic outbreak of meningitis and meningoencephalitis, caused by West Nile virus, in the Krasnodar territory and Volgograd region (preliminary report)].

Sera from 102 inpatients from the Volgograd region (64) and Krasnodar region (38) were tested for antibodies to West Nile (WN) virus in hemagglutination inhibition (HI) test and for IgM and IgG antibodies in enzyme immunoassay (EIA). Diseases etiologically associated with WN virus were diagnosed in 81 patients: in 50 out of 64 in the Volgograd region and in 31 out of 38 in the Krasnodar region, which makes 79.4%.

[The effectiveness of lanthanide immunofluorescence and immunoenzyme analyses in differentiating viruses of the tick-borne encephalitis complex].

Comparison of the efficacy of time-resolved fluoroimmunoassay (TR-FIA) and two variants of enzyme immunoassay: conventional (EIA-1) and one using biotin-streptavidin system (EIA-2), in differentiation of viruses of the tick-borne encephalitis complex showed that, their specificity being similar, the TR-FIA method was 2-4 times as sensitive as EIA-2 and 8-32 times as sensitive as EIA-1. When the reactivity of the antigens was assessed by titers, the differentiating capacity was found to be similar and to depend upon the specificity of "sandwich"-forming antibodies and the sensitivity of the immunoassay. When the reactivity of the antigens was assessed by relative reactivity in 4 test systems of different compositions, the differentiating capacity of TR-FIA was higher than that of EIA-1 and EIA-2 which allowed additional differentiation of 2 groups of viruses on the basis of qualitative characteristics of reactivity.

Monoclonal antibodies identify the NS5 yellow fever virus non-structural protein in the nuclei of infected cells.

Eight monoclonal antibodies (MAbs) derived using yellow fever (YF) virus (French viscerotropic virus strain) labelled the nuclei (wild-type strains) and/or the nucleoli (vaccine strains) of cells infected with different strains of YF virus. The specificity of these antibodies for YF virus-infected cells was confirmed using MAbs that bind only the YF virus envelope glycoprotein. The characteristics of fluorescent labelling in the nuclei and nucleoli of both normal cells and of nuclei separate from cell cytoplasm confirmed that the antigen was inside the nucleus rather than on the outer surface of the nuclear membrane.

Detection of tick-borne encephalitis virus in ixodid ticks collected in natural foci by time-resolved fluoroimmunoassay.

Time-resolved fluoroimmunoassay (TR-FIA) was used for the first time for evaluation of infestation of ixodid ticks with tick-borne encephalitis virus. Comparison of TR-FIA results with those obtained in enzyme immunoassay and by virus isolation confirmed the high efficacy of the method in question. Positive results of TR-FIA coincided with the data of virus isolation in 83.

[A monoclonal antibody study of the receptor area of the Venezuelan encephalitis virus].

The receptor region for virus-cell interaction in Venezuelan equine encephalomyelitis (VEE) and Eastern equine encephalomyelitis (EEE) viruses was studied using a panel of 17 monoclonal antibodies (MCA). They were able to block agglutination of goose erythrocytes. The dominant role of glycoprotein E2 in the formation of viral receptor for EEE and VEE viruses was demonstrated.

[The immunity generated in white rats vaccinated with strains of the Venezuelan equine encephalomyelitis virus].

The existence of virulence gradient in the main members of Venezuelan equine encephalomyelitis virus complex (VEE) was established by subcutaneous inoculation of immunologically competent outbred rats weighing 50-70 g. The virulence of the strains may be judged by a parameter such as the weight of the animal in 5 or 10 days after inoculation. The highest degree of protection was observed in the animals immunized with strain 15, the least in those immunized with strain 230.

[The demonstration of the Venezuelan equine encephalomyelitis virus by the method of indirect lanthanide immunofluorescent analysis].

A test system of indirect time-resolved fluoroimmunoassay (TR-FIA) was developed and tested on an alpha-virus, Venezuelan equine encephalomyelitis virus. The indirect TR-FIA test system was shown to be highly effective in the detection of antigens of this virus. Not differing in specificity from the direct TR-FIA, the newly developed test system was 4 times as sensitive.

[The differentiation of viruses in the Venezuelan equine encephalomyelitis complex by using monoclonal antibodies and lanthanide immunofluorescence analysis].

Potentialities of differentiation between Venezuelan equine encephalomyelitis (VEE) complex viruses by time-resolved fluoroimmunoassay and enzyme immunoassay were studied. For this, 4 test systems were used based on different combinations of native and labeled polyclonal antibodies to VEE virus, strain Trinidad, and monoclonal (MCA) antibody MAK 14-7 to protein EL of this virus. The maximal sensitivity and specificity was achieved in the test system formed from native MCA MAK 14-7 for sensitization of the solid phase and labeled polyclonal immunoglobulins for demonstration of the test results.

[The design and trial of conjugates for performing lanthanide immunofluorescence analysis].

The possibility of using a number of complexons for labeling of antibodies to Venezuelan equine encephalomyelitis virus and to adenovirus with europium ions was studied. The resultant conjugates, irrespective of the type of complexon, were shown to retain their immunochemical activity and could be used for lanthanide immunofluorescence analysis of virus-specific antigens.

Antigenic analysis of tick-borne encephalitis complex viruses by time-resolved fluoroimmunoassay with monoclonal antibodies.

The antigenic structure of 5 strains of tick-borne encephalitis (TBE) virus and 7 other viruses of the TBE complex was examined by the highly sensitive and specific technique of time-resolved fluoroimmunoassay (TR-FIA). A collection of 8 monoclonal antibodies to the Austrian strain. Neudörfl, was used in this study.

[The use of sectional polystyrene plates in the set-up of lanthanide immunofluorescence analysis].

The authors have examined the possibility of using sectional polystyrene plates, made in this country, in time-resolved fluoroimmunoassay (tr-FIA) with Venezuelan equine encephalomyelitis and tick-borne encephalitis arboviruses, and with influenza A virus. The plates presensitized with specific antibodies were found fit for the detection of the antigens of the above viruses. These plates are not recommended for the detection of influenza A virus-specific proteins adsorbed directly onto the microplate surface.

[Monoclonal antibodies cross-reacting with the tick-borne encephalitis virus and with the Venezuelan equine encephalomyelitis virus].

Employment of radioimmunoassay led to the demonstration of serological crossing between tick-borne encephalitis (TBE) virus and Venezuelan equine encephalomyelitis (VEE) virus. Using hybridoma technology, three hybridomas were produced secreting monoclonal antibodies (MAb) cross-reacting with these two viruses. With MAb, the epitope of binding of these antibodies was shown to be located on protein E of TBE virus and protein E1 of VEE virus.

[Virological study of cases of sandfly fever in Afghanistan].

Three strains (Af-1008, Af-1038, and Af-130) of Neapolitan sandfly fever virus (NSFF) and 2 strains (Af-1028 and Af-83) of Sicilian sandfly fever virus (SSFF) were isolated from febrile patients among soldiers of the limited military contingent of Soviet troops in Afghanistan in May-August, 1986-1987. The viruses were isolated in neonate mice and identified by indirect immunofluorescence, complement-fixation tests and plaque reduction neutralization test in Vero E6 and SPEV cells. The new NSFF strains in serological tests differed slightly from the original Sabin strain and completely differed from Toskana virus.

[Antigenic analysis of tick-borne encephalitis virus group using monoclonal antibodies and immunofluorescence].

The study included 18 monoclonal antibodies (MAb) to E- or NS1-antigens tested by immunofluorescence with tick-borne encephalitis (TBE) complex viruses. MAb were induced to 3 strains of TBE virus: the pathogenic 4072 strain isolated from a patient; the Skalica strain of low pathogenicity; and the Neidorf strain isolated from ticks. According to their reactivity to complex viruses, MAb comprised 3 groups: monospecific for TBE virus (T6, T15) which detected tick-borne encephalitis virus alone; widely cross-reactive with 4-6 viruses of the complex (NEK, KEN, T7, T9); and partially complex-reactive (T11, T12, T13, T33/3) and bound to 2-3 viruses of the complex.

[Hybridomas producing monoclonal antibodies to Crimean hemorrhagic fever virus].

A series of hybridomas producing monoclonal antibodies to Crimean hemorrhagic fever virus was obtained and their cultural properties were characterized. HEMA-12 and HEMA-24 secreted monoclonal IgG2b antibodies, HEMA-101 secreted monoclonal IgG1 antibodies, HEMA-31, HEMA-9 and HEMA-11 secreted monoclonal IgG2 antibodies. According to the results of the indirect immunofluorescence test, the titer of specific immunoglobulins in the culture fluid was 1:16-1:32, but sometimes reached 1:64-1:128.

[Characteristics of the monoclonal antibodies induced by the Crimean hemorrhagic fever virus].

Twelve lines of hybridomas secreting monoclonal antibodies (MCA) have been generated by fusion of spleen lymphocytes of BALB/c mice immunized with crude Crimean hemorrhagic fever virus (CHF). The hybridomas multiply actively in vitro (over 50 passages) and as ascitic tumors in the abdominal cavity of BALB/c mice. MCA were characterized by indirect immunofluorescence (IF), complement fixation (CF), biological neutralization test (NT), agar gel diffuse precipitation tests, and by the type of immunoglobulins.