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Biomedical subjects

S Ia Gaĭdamovich

Publications and source records attributed to S Ia Gaĭdamovich.

At least 19 recordsLinked to original sources

[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.

Antigens, Viral↗

[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. The titer of antibodies in ascitic fluid amounted to dilutions of 10(4)-10(5). Hybridomas were cloned by the method of ultimate dilutions. The injection of 5-15 million HEMA cells into the abdominal cavity of BALB/c mice induced the formation of ascitic tumors in the animals within 7-11 days and the accumulation of ascitic fluid in a volume of 1-4 ml. Hybridomas, found to be capable of passage from mouse to mouse, underwent 5-16 passages during the term of observation.

Animals↗

[Monoclonal antibodies to the yellow fever virus].

A highly technological Yel-2 hybrid cell clone was isolated. The clone produces monoclonal antibodies to protein E of the yellow fever virus (Dakar strain). The Yel-2 hybridoma was cloned by the method of limiting dilutions. By the data of indirect immunofluorescence the titre of the specific antibodies reached 1:128 in the culture fluid and 1:10240 in the ascitic fluid. The Yel-2 antibodies had no cross reactions with forest-spring encephalitis, Dengue 2 and Dengue 4 viruses. In the hemagglutination inhibition test the activity of the Yel-2 ascitic preparations was observed at a dilution of 1:50000 while the complement fixation test did not reveal it. Administration of the Yel-2 cells into the abdominal cavity of mice BALB/c induced development of ascitic tumors in 97 per cent of pristane-sensitized mice and in 90 per cent of nonsensitized mice. The hybridoma was successfully transplanted from mouse to mouse (more than 20 passages during the observation period) and maintained high constant levels of specific antibody secretion. The high ascite forming capacity of the Yel-2 hybridoma provided decreasing of the cell dose administered to the mice from 10(7) to 10(4) cells per mouse.

Abdominal Neoplasms↗

[Diagnostic preparations based on monoclonal antibodies].

The specific activity of diagnostic preparations based on monoclonal IgM MAK-14-7 interacting with the antigens of the Venezuela equine encephalomyelitis virus, monoclonal IgG KAMA-51 interacting with the antigens of the forest spring encephalitis virus and monoclonal IgA OKA and IgM OKA binding to the antigens of the vaccine virus was studied by the enzymatic immunological and immunofluorescent tests. Both the ascitic preparations of the antibodies and the fluorescein isothiocyanate-conjugated reagents such as MAK-FITC, KAMA-FITC and OKA-FITC were characterized by high specificity and activity. The specific sensitivity and activity of the monoclonal immunoglobulins was completely maintained in the mixed and combined preparations.

Animals↗

[Conditions for forming ascitic tumors in hybridoma cultivation in vivo].

The conditions of the formation of ascitic cells in BALB/c mice injected with hybridoma cells were studied. All the hybridomas under study, producing monoclonal antibodies to viral antigens, induced the formation of ascitic tumors when introduced into the abdominal cavity of BALB/c mice pretreated with sensitizing agents. In the mice pretreated with pristane hybridoma cells took at a rate of 43-80% and in the mice pretreated with Freund's complete adjuvant, 31-70%. Angara oil and perfume oil, as well as Bayol F, were less effective. The time of the formation of ascites was inversely proportional to the dose of the injected cells, while the volume of ascitic fluid depended rather on the type of hybridoma and not on the dose of the injected cells. The study showed that the use of physiological saline or culture medium without serum for washing the abdominal cavity of mice after withdrawing ascites permitted the additional collection of 2.6-13.7 million hybrid cells, as well as a considerable amount of immunoglobulins.

Animals↗

[Antiviral activity of proteinase inhibitors in cultured cells infected with alpha-viruses].

The ability of synthetic inhibitors of trypsin-like (TLCK) and chymotrypsin-like (TPCK) proteinases and natural antiproteinase oligopeptides of animal (aprotinin) and microbial (enzistatin) origin to suppress multicycle replication of different alpha viruses (Semliki, Sindbis, Venezuelan equine encephalomyelitis viruses) in cultured cells was studied. Antiviral activity was found to be induced by TPCK and aprotinin (Gordox). These compounds were shown to reduce virus yield 100-fold and to prevent the involvement of cells into infection process. The mechanisms of antiviral activity and chemotherapeutic possibilities of antiproteinase compounds are discussed.

Alphavirus↗

[Identification of monoclonal antibodies against protein E1 of venezuelan equine encephalomyelitis virus blocking the hemagglutinating but not the infective activity of virions].

Cellular clone (MAK 14-7), producing antibodies against the virus of Venezuela equine encephalomyelitis (VEE), strain 230, was isolated using the standard hybridomata technology. Monoclonal antibodies neutralized the viral hemagglutinating activity leaving the infectious one intact. Monoclonal antibodies from MAD 14-7 reacted specifically with viral glycoprotein E1 as registered by the immunoprecipitation technique. The topography of antigenic determinants of viral E1/E2 glycoprotein dimer forming the virions outer spikes is discussed in connection with the results obtained.

Animals↗

[Avidity criteria in assessing the functional activity of antigens, antibodies and non-specific serum inhibitors on a model of the kinetic reaction of hemagglutination suppression with arboviruses].

The functional activity of some arboviruses of groups A and B, of the antibodies and serum inhibitors was studied on a model of the kinetic hemagglutination inhibition test (HAI) by different avidity criteria (velocity, completeness and stability of formation of a neutral complex). The avidity indices of the antigens, antibodies and the inhibitors proved to depend on the group, species and strain peculiarities of the arboviruses, the method of preparation of the antigen, the biological species of the donor of the immune and normal blood sera, the method of treatment of the sera and a number of other factors. There proved to be no constan-correlation between the avidity of the strain and the avidity of the serum immune to it. Inhibitors of the normal rabbit and human sera were not less effective in comparison with the specific antibodies to a number of viral strains of tick-borne encephalitis and Japanese encephaliti or even exceeded them by the avidity indices to the antigens in the HAI test. The most active (functionally) strains can be recommended for obtaining high-quality viral (antigenic and serum) preparations.

Animals↗

[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%. Specificity of antibodies to WN virus was confirmed in HI and EIA with WN antigens, related flaviviruses (Japanese encephalitis and yellow fever), and Sindbis alfavirus. A considerable number and the incidence of WN infection suggest that an epidemic caused by WN virus occurred in the Krasnodar and Volgograd regions in summer 1999.

Antibodies, Viral↗

[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.

Antigens, Viral↗