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Biomedical subjects

O G Andzhaparidze

Publications and source records attributed to O G Andzhaparidze.

At least 19 recordsLinked to original sources
PubMed1994

Construction and expression in Escherichia coli of hybrid genes composed of sequences encoding diphtheria toxin and human CD4 receptor.

Derivatives of natural toxins possessing substituted receptor-recognition domains of different specificities can be used as instruments for the selective elimination of target cells. We have constructed two different types of hybrid genes that encode proteins composed of diphtheria toxin (DT) lacking the C-terminal residues that mediate toxin binding fused with the N-terminal region of human CD4 (Lys10 to Glu152). One of these hybrids encodes a protein with CD4 at the N terminus, while the other encodes a protein with CD4 at the C terminus. The stability of these two proteins was dramatically different. We could not detect a full-size product when the first construct was expressed in Escherichia coli. In contrast, proteins encoded by the second construct were more stable. In the latter case, the amount of full-size hybrid protein was 1-2% of the total cell protein. We speculate on the involvement of the region that resembles the processing site of Pseudomonas aeruginosa exotoxin A in the proteolytic degradation of the product encoded by the first type of hybrid.

Amino Acid Sequence↗
PubMed1991

[The use of the indirect hemagglutination reaction for the serodiagnosis of HIV infection].

An assay system, based on the passive hemagglutination test and permitting the serodiagnosis of HIV infection with correct results in more than 99% of cases, has been developed. Three kinds of freeze-dried erythrocyte diagnostica (with shelf life exceeding 6 months), possessing high serological activity and sensitized with recombinant gene-engineering polypeptides, have been obtained. The proposed assay system is highly promising for mass examination of sera for the presence of antibodies to HIV due to the simplicity of assay techniques, the possibility of storing the diagnostica within a wide range of temperatures (4 degrees-30 degrees C) and obtaining results in a short time (3 hours).

AIDS Serodiagnosis↗
PubMed1991

[Cloning and expression of the CD4 receptor gene from human T-lymphocytes in Escherichia coli cells].

The gene for the CD4-membrane glycoprotein-receptor for HIV has been cloned. The 179 amino acids fragment of the CD4-receptor responsible for binding of gp120 HIV glycoprotein has been fused with beta-galactosidase and shown to be expressed in Escherichia coli cells. The recombinant protein in ELISA and immunoblotting techniques reacts with the monoclonal antibodies OKT4A and Leu3A known to block the interaction between the CD4 and gp120 HIV glycoprotein. The recombinant protein can be used for different scientific and practical purposes including studying of the mechanisms for HIV interaction with the sensitive cells as well as for viral gp120 protein purification, etc.

Base Sequence↗
PubMed1988

Preparation of Hybridomas producing monoclonal antibodies against human interferon.

To prepare hybridomas secreting monoclonal antibodies (MoAb) against human alpha-interferon (alpha-IFN), BALB/c mice were immunized with IFN produced in Namalwa cells. Native alpha-IFN, as well as partially purified or on cellulose adsorbed alpha-IFN preparations were used for immunization. Seven hybridomas continuously secreting IgG against human alpha-IFN were prepared by fusion of splenocytes from immunized donors with the mouse myeloma cells. MoAb reacted in ELISA as well as in neutralization test with human lymphoblastoid, leukocytic and recombinant alpha-IFN.

Animals↗
PubMed1987

Non-infectious morphologically altered nucleocapsids of measles virus from persistently infected cells.

Persistent measles virus infection of human HEp-2 or L-41 cells was accompanied by pronounced structural and functional changes of isolated intracellular viral nucleocapsids (NCs). The bulk of persistent NCs possessed altered conformation and a "string-of-beads" appearance, contained substantial amounts of subgenomic size RNAs, exhibited reduced transcriptase activity in vitro and lacked infectivity on transfection of susceptible cells. Immunogold staining revealed negligible binding of anti-P protein monoclonal antibodies to the "string-of-beads" type NCs, thus suggesting their non-functional state.

Capsid↗
PubMed1983

Chronic non-cytopathic infection of human continuous cell lines with mumps virus.

Chronic infection with a vaccine strain of mumps virus (MV) was produced and studied in human cell cultures L-41 and HEp-2. The establishment and course of the infection was not accompanied by cytopathic changes. Among probable protective factors (mechanisms) interferon (IFN) was detected in L-41 culture and defective interfering particles in either cell culture. Their role in the establishment and maintenance of chronic infection was not confirmed, however.

Animals↗
PubMed1981

Comparative study of rabies virus persistence in human and hamster cell lines.

Persistent infections by rabies virus in BHK-21/13S and HEp-2 cells were studied comparatively. No evidence of interferon production, selection of virus-resistant cells, or integration of the viral genome could be found. Persisting viruses replicated efficiently at 34, 36, and 40 degrees C. Both persistently infected cultures released defective interfering virus particles. A cyclical pattern of infection, which was not characteristic of the persistently infected HEp-2 system, was observed in persistently infected BHK cultures. The virus from persistently infected BHK cultures lost its virulence for mice, whereas the virus from persistently infected HEp-2 cultures retained mouse-killing capacity for more than 3 years.

Animals↗
PubMed1979

A comparative study of tick-borne encephalitis virus RNA synthesis in acutely and persistently infected cells.

Rate zonal and buoyant density gradient centrifugation did not reveal any difference between tick-borne encephalitis virus virions released from acutely or persistently infected cells. All three RNA species characteristic for flavivirus replication were found both in acutely or persistently infected cells, but increased levels of intracellular 42S RNA polyadenylation was observed in persistently infected cells.

Animals↗
PubMed1979

Live tissue culture influenza vaccine for oral administration. I. Specific immune response to monovaccine A (H3N2) in volunteers.

Oral immunization of volunteers with a live tissue culture influenza A (H3N2) vaccine induced an increase in virus neutralizing (VN), haemagglutination inhibiting (HI) and neuraminidase inhibiting (NI) antibody. The dynamics of antibody and IgM and IgG immunoglobulin formation in the blood depended to a great extent on their prevaccination levels. The highest per cent of seroconversions was observed after the 3rd vaccination: a 4-fold or greater rise of VN antibody was found in 80% (titre increase by 3.0 log2 units), of HI antibody in 70% (titre increase by 2.6 log2 units) and NI antibody in 73% (titre increased by 2.5 log2 units) of the volunteers. The level of IgG increased after each vaccination but its highest level did not coincide in time with the maximum antibody production. High titres of the antibodies studied were recorded 1-2 months after the 3rd vaccination, irrespective of their prevaccination levels.

Administration, Oral↗