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Biomedical subjects

N V Gnuchev

Publications and source records attributed to N V Gnuchev.

At least 19 recordsLinked to original sources
PubMed2005

[Transcription and mRNA splicing of the human lactoferrin gene controlled by the regulatory region of the bovine alphaS1 casein gene in the mammary gland of transgenic mice and in mouse embryonic stem cells].

The regulatory region of the bovine alphaS1 casein gene was used to obtain two genetic constructs for expression of human lactoferrin in the mammary gland of transgenic animals. Several transfected mouse embryonic stem cell (ESC) lines and primary transgenic mice were generated with these constructs. Recombinant lactoferrin was not detected in milk of transgenic mice by Western blotting. However, a recombinant transcript was found in RNAs isolated from mammary glands of transgenic females during lactation and from transfected ESC lines.

Animals↗
PubMed2005

[Catalytic autoantibodies in autoimmune myocarditis: clinical and pathogenetic implications].

AIM: To evaluate pathogenetic and clinical significance of autoantibodies (AAB) with catalytic activity in the serum of patients with autoimmune myocarditis (AM). MATERIAL AND METHODS: The study was made on the sera from 99 patients with AM of different course: malignant, benign, myocardiosclerosis (MCS). In addition to standard immunological parameters, the study was made of serum levels of anticardiomyosine-antiCM (protabzymes) and anti-DNA (DNA-abzymes) of AAB. After obtaining anti-CM and anti-DNA IgG-AT, we determined non-specific and specific proteolytic activity of anti-CM. RESULTS: Maximal specific activity of protabzymes was seen in 73% patients with malignant AM, it correlated with blood levels of anti-CM AAB, DNA-abzymes activity was very high in 45% patients. In MCS proteolytic activity of autoAT was absent in 61% patients. In benign AM occurrence of protabzymes was confirmed in 35% cases. Elevated DNA-hydrolyzing activity of DNA-abzymes occurred in 13% cases. The activity had no significant correlation with serum titers of AB. In MCS proteolytic activity of AAB was absent in 61% cases, but high activity of anti-CM AAB was in 28%. The activity of DNA-abzymes in 44% ranged considerably which, in seropositive cases, detected significant correlation with serum titers of DNA-binding autoAT. CONCLUSION: Evaluation of catalytic activity of AAB may be considered as a criterial test assessing the stage, clinical variants and severity of AM. It also permits formulation of the disease prognosis and its possible outcomes.

Antibodies, Catalytic↗
PubMed2002

Anti-DNA autoantibodies reveal toxicity to tumor cell lines.

Cytotoxicity of anti-DNA autoantibodies from sera of SLE and CLL patients was assayed on permanent cell lines L929, HL-60, Raji, and K562. L929 cells appeared to be the most sensitive to antibody treatment. DNA-hydrolyzing properties of the same autoantibody preparations were analyzed in parallel. The data obtained outlined the correlation between cytotoxicity and DNA-hydrolyzing properties of these autoantibodies. It was shown that treatment of the cells with cytotoxic anti-DNA autoantibodies induced internucleosomal DNA fragmentation and Annexin V binding to the cell surface characteristic of apoptotic pathway of cell death. A time-dependent profile of antibody-mediated toxicity to L929 cells suggested recruitment of at least two distinct mechanisms of cell death. The first peak of cell death observed in 3 h of incubation was completely inhibited by preincubation of cells with caspase inhibitor YVAD-CHO, while the second increase in cell mortality (18-30 h) persisted. Possible mechanisms for anti-DNA autoantibody cytotoxicity are discussed.

Antibodies, Antinuclear↗
PubMed2002

Antibody proteases: induction of catalytic response.

Most of the data accumulated throughout the years on investigation of catalytic antibodies indicate that their production increases on the background of autoimmune abnormalities. The different approaches to induction of catalytic response toward recombinant gp120 HIV-1 surface protein in mice with various autoimmune pathologies are described. The peptidylphosphonate conjugate containing structural part of gp120 molecule is used for reactive immunization of NZB/NZW F1, MRL, and SJL mice. The specific modification of heavy and light chains of mouse autoantibodies with Val-Ala-Glu-Glu-Glu-Val-PO(OPh)2 reactive peptide was demonstrated. Increased proteolytic activity of polyclonal antibodies in SJL mice encouraged us to investigate the production of antigen-specific catalytic antibodies on the background of induced experimental autoimmune encephalomyelitis (EAE). The immunization of autoimmune-prone mice with the engineered fusions containing the fragments of gp120 and encephalitogenic epitope of myelin basic protein (MBP(89-104)) was made. The proteolytic activity of polyclonal antibodies isolated from the sera of autoimmune mice immunized by the described antigen was shown. Specific immune response of SJL mice to these antigens was characterized. Polyclonal antibodies purified from sera of the immunized animals revealed proteolytic activity. The antiidiotypic approach to raise the specific proteolytic antibody as an "internal image" of protease is described. The "second order" monoclonal antibodies toward subtilisin Carlsberg revealed pronounced proteolytic activity.

Animals↗
PubMed2001

[Production of recombinant endostatin in milk from transgenic mice].

Using the bovine alpha S1-casein gene, a genetic construct with an endostatin-coding fragment of the mouse collagen XVIII cDNA was designed to express endostatin in milk of transgenic animals. Several transgenic mice were obtained. The mice secreted endostatin in milk at 70-300 ng/microliter and transmitted this character to their progeny.

Animals↗
PubMed2001

[DNA-abzymes and their clinical significance in systemic lupus erythematosis].

AIM: To evaluate occurrence of DNA-abzymes with catalytic (DNA-hydrolysing) and cytotoxic properties in patients with systemic lupus erythematosus (SLE) for examination of clinical value of DNA-abzymes in diagnosis of autoimmune syndrome and apoptosis level in different variants of immunopathology. MATERIAL AND METHODS: The study group consisted of patients with verified SLE diagnosis (n = 120). They were compared to 72 patients with rheumatoid arthritis (RA), 82 patients with scleroderma systematica (SS), 60 patients with discoid lupus erythematosus (DLE), 88 patients with focal scleroderma (FS) and 198 autoimmune uveitis (AU) patients. 128 donors served control. Catalytic and cytotoxic activity of DNA-abzymes were determined by methods of molecular biology and enzymology. All the patients were examined for blood levels of IgG, IgM and IgA, anti-DNA, anti-Sm and other IgG-autoantibodies, CIC titers, phagocyting activity, content of main D-cell subpopulations. Key immunoregulatory indices were also estimated. RESULTS: DNA-abzymes were detected more often in SLE and RA patients. In SLE, catalytic and cytotoxic activities of DNA-abzymes reached their maximum. There was a correlation with leading clinicoimmunological signs of SLE. The disease was most severe with apparent immunopathology in patients with maximal catalytic and cytotoxic activity of DNA-abzymes. With lowering cytotoxic activity of DNA-abzymes more patients demonstrate low SLE activity without severe organic lesions and alleviated symptoms of immunopathology. CONCLUSION: An important role of DNA-abzymes in pathogenesis of SLE is shown. They are also valuable tools in diagnosis of various clinicoimmunological variants of the disease.

Apoptosis↗
PubMed2000

Nonlymphoid cultured cells possess a system controlling cellular compatibility.

We show that various nonlymphoid cultured cells can activate the production of cytotoxic factors in response to direct contact with cells of a different kind. Accumulation of cytotoxic factors in the medium was detected 1 h after contact of K562 and L929 cells or after contact of L929 cells with purified membranes of K562 cells. TNF-alpha or immunologically related proteins, or both, but not Fas-ligand or lymphotoxin, were also accumulated in membranes of K562 and L929 cells shortly after these cells had been allowed to contact each other. The cytotoxic factors expressed by nonlymphoid cells trigger apoptosis of target cells. These observations strongly suggest that nonlymphoid cells possess molecular mechanisms controlling cellular compatibility.

Animals↗
PubMed2000

[tag7 Gene and gene therapy of cancer].

Modern gene therapeutic approaches towards the treatment of malignant neoplasms are discussed. Specifically, results of the first experiments on the development of vaccines on the basis of tumor cells modified with various cytokines and activation molecules are described. We compare effectiveness of different cytokines used for modification of tumor cells are made and consider possible mechanisms of vaccine action. The reasons for impossibility of the development of effective endogenous antitumor immunity are examined. The results of comparative analysis of the Tag7 protein antitumor activity are presented. This evidence clearly shows that Tag7 is a promising agent for anticancer therapy.

Animals↗
PubMed2000

[Cloning and study of novel mammalian genes with structural homology with phage lysozyme].

The mouse tag7 gene was cloned and characterized in our previous works. This work is devoted to identifying and cloning its homologs. The human homolog of the tag7 gene was cloned. Data of analysis of the primary structure of the human tag7 and results from the study of the production of the corresponding protein in human organs and tissues indicate that this gene plays a major role in the mammalian immune system. The mouse and human tagL gene carrying an extended region of structural homology with the tag7 gene was detected by computer analysis and was subsequently cloned. Sequence analysis suggested the possible membrane localization of the gene, whereas the specific expression pointed to the role of this gene in the immune system. Both genes, tag7 and tagL, were localized in the human chromosome 19.

Amino Acid Sequence↗
PubMed1999

Resistance to tumor necrosis factor induced apoptosis in vitro correlates with high metastatic capacity of cells in vivo.

TNF is one of the cytokines secreted by the cells of the immune system. Our data demonstrate that those cell lines lacking capability to form metastatic tumors in vivo are susceptible to TNF induced apoptosis in vitro. However, cell lines with high metastatic potential are resistant to TNF in vitro. Furthermore, the same cell lines were resistant to cytolytic action of other cytotoxic proteins secreted by LAK cells. Our data showed that TNF resistance in vitro correlates with the increased level of transcription factor NF-kappaB. This finding may provide a tool to improve current protocols of immunotherapy and insights to how tumor cells are or are not killed by LAK cells.

Animals↗
PubMed1999

Genomic structure and chromosomal localization of the mouse persyn gene.

Synucleins are a family of small intracellular proteins expressed mainly in the nervous system. The involvement of synucleins in neurodegeneration and malignancy has been demonstrated, but the physiological functions of these proteins remain elusive. Further studies including generation of animals with modified persyn expression are necessary to clarify the functions of these proteins and the mechanisms of their involvement in human diseases. We cloned and determined the organization and chromosomal localization of the mouse gene coding for persyn, a member of the synuclein family. The gene is composed of five exons, and its general structure is very similar to that of the human persyn gene. Using fluorescence in situ hybridization, we assigned the persyn gene to the boundary of bands B and C on mouse chromosome 14. We found a fragment of the gene that directs expression of the persyn protein in sensory neurons and could be used for generation of transgenic animals.

3T3 Cells↗
PubMed1998

Novel functional activities of anti-DNA autoantibodies from sera of patients with lymphoproliferative and autoimmune diseases.

DNA-hydrolyzing activity of IgG autoantibodies from sera of patients with various types of lymphoproliferative diseases was investigated. The association of DNA-hydrolyzing activity with the antibody (Ab) fraction has been proved by newly developed affinity-capture assay. Study of abzyme incidence in blood tumors and systemic lupus erythematosis (SLE) revealed linkage of anti-DNA Ab catalysts to mature B-cell tumors, and increased probability of DNA-abzymes formation on the background of autoimmune manifestations. These data suggest possible similarity between mechanisms of abzyme formation in SLE and B-cell lymphomas. A new mechanism of formation of DNA-specific catalytic Abs has been proposed based on the increased crossreactivity of polyclonal DNA-abzymes to DNA-depleted nuclear matrix proteins. The possibility of the abzyme production as Ab to the energetically destabilized ground state of the antigen has been discussed. Preliminary results were obtained that indicate the complement-independent cytotoxicity of anti-DNA autoantibodies isolated from blood of patients with SLE and chronic lymphocytic leukemia.

Antibodies, Antinuclear↗