[Expression of receptors for human alpha- and gamma-interferons on the surface of peripheral blood mononuclear cells in viral infections]. / Ekspressiia retseptorov dlia chelovecheskikh alpha- i gamma-interferonov na poverkhnosti mononuklearnykh kletok perifericheskoi krovi pri virusnykh infektsiiakh.

Expression of receptors on peripheral blood mononuclears of donors and patients with viral infections during therapy was studied using FITC-labeled monoclonal antiidiotypical antibodies with the "internal image" of human alpha- and gamma-interferons and monoclonal antibodies to these interferons. Activation of the immune system caused by infection modifies the expression of interferon receptors and leads to appearance of membrane-bound interferons, mainly gamma-interferon.

[Use of a latex-agglutination test for determining anti-measles antibody titer]. / Ispol'zovanie testa lateks-aggliutinatsii dlia opredeleniia titrov protivokorevykh antitel.

A new diagnostic agent for microtitration of antimeasles antibodies, making use of polyacrolein microspheres conjugated with purified measles virus has been developed. Parallel titration of blood sera of children and adults in latex agglutination test and in routine test (hemagglutination inhibition, passive hemagglutination, immunofluorescent tests) demonstrated a sufficient specificity of the new test, sensitivity compatible to that of hemagglutination inhibition, and correlation of the results of all tests.

[Stability and virus-inhibiting effect of recombinant receptor toxins based on the human CD4 receptor and diphtheria toxin]. / Stabil'nost' i virusingibiruiushchee deistvie rekombinantnykh retseptorotoksinov na osnove CD4-retseptora T-limfotsitov cheloveka i difteriinogo toksina.

The causes of differences in the stability of CD4 receptor and diphtherial toxin based recombinant receptorotoxins synthesized in E.coli and differing by their primary structure were under study. Insertion of a CD4 receptor fragment, responsible for HIV binding, on the N terminus of hybrid protein was found to lead to a drastic reduction of the stability of the hybrid polypeptide in E.coli and to impossibility of obtaining full-size protein product. In vitro experiments on a model of human T lymphocyte culture demonstrated that recombinant receptorotoxin stably expressed in E.coli inhibited the cytopathic effect of type 1 HIV and the effect of syncytium formation induced by the virus.

[The protective effect of monoclonal anti-idiotypic antibodies in experimental herpes infection]. / Protektivnyi éffekt monoklonal'nykh antiidiotipicheskikh antitel pri éksperimental'noi gerpeticheskoi infektsii.

The protective effect of monoclonal anti-idiotypic antibodies m(anti-ID)Abs, simulating the biologic effects of human alpha interferons, were studied in male guinea pigs with genital herpes simplex. Therapeutic effect of m(anti-ID)Abs daily applied as liquid dosage form and as suppositories+ was assessed. Experiments demonstrated that m(anti-ID)Abs in liquid dosage form to a different measure decreased the severity of urogenital infection in guinea pigs and that m(anti-ID)Abs-25 completely prevented the development of grave infection.

[A nonisotopic method of quantitative PCR analysis in diagnosing HIV infection]. / Neizotopnyi metod kolichestvennogo PTsR-analiza v diagnostike VICh-infektsii.

A nonisotopic method for the detection of HIV DNA has been developed, based on the use of avidin-biotin complex to identify the products of polymerase chain reaction (PCR). Biotin label integrated in deoxyuridine triphosphate (bio-11-dUTP) was incorporated in the structure of amplified fragments in the course of PCR. The resultant products were identified in hybridization reaction with specific HIV DNA adsorbed on polystyrene plates. The suggested method was not inferior to the traditional radioisotope method in sensitivity and specificity and helped quantitatively assess the results of experiments using an objective criterion--optic density value.

[Primers for the nef gene in the diagnosis of HIV infection using the polymerase chain reaction]. / Praimery k genu nef v diagnostike VICh-infektsii s pomoshch'iu polimeraznoi tsepnoi reaktsii.

A new system of primers and internal probe identifying the nef gene of HIV-1 was selected and tested for the laboratory diagnosis of HIV infection by means of PCR. The proposed primers and probe by their characteristics approached the optimal ones for PCR diagnosis. The diagnostic value of the above system was confirmed by the PCR analysis of blood samples from 29 patients including subjects with a doubtful diagnosis of HIV infection. The results of the PCR analysis using primers nef1/nef2 correlated with the results obtained by employing the widely used primers for the gag gene SK38/SK39 and attested to the high specificity and diagnostic efficiency of the proposed system.

[The antiviral action of recombinant forms of the human T-lymphocyte CD4 receptor]. / Protivovirusnoe deistvie rekombinantnykh form CD4-retseptora T-limfotsita cheloveka.

A recombinant protein containing the first 179 N-terminus amino acids of human T-lymphocyte CD4-receptor was synthesized in E. coli cells. This recombinant protein was shown to interact with OKT4A and Leu3a monoclonal antibodies competing with HIV gp120 glycoprotein for binding with the native CD4 receptor. Experiments in vitro in human T-lymphocyte cultures showed that the recombinant CD4-protein in concentrations of 1 to 10 micrograms/ml inhibited the virus-induced syncytium formation, HIV replication in cell culture, synthesis of HIV reverse transcriptase and other virus-specific proteins, that is, behaved as a HIV inhibitor.

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.

[The antiviral action of recombinant receptorotoxins based on the diphtheria toxin and the human T-lymphocyte CD4-receptor]. / Protivovirusnoe deistvie rekombinantnykh retseptorotoksinov na osnove difteriinogo toksina i CD4-retseptora T-limfotsitov cheloveka.

A number of vectors expressing in E. coli hybrid proteins (receptorotoxins) composed of diphtheria toxin lacking the C-terminal region and CD4-receptor fragment including N-terminal region of the natural protein have been constructed. The receptorotoxins consisting of the CD4 fragment in their N-terminal region were more stable. These recombinant receptorotoxins were cultured with HIV-infected Hut-78 cells and were shown to block HIV infection in vitro.

[The isolation and characteristics of monoclonal antibodies to recombinant proteins of HIV-1 and HIV-2--the env and gag gene products]. / Poluchenie i kharakteristika monoklonal'nykh antitel k rekombinantnym belkam VICh-1 i VICh-2--produktam genov env i gag.

Ten hybridomas secreting monoclonal antibodies (Mab) against recombinant HIV-1 and HIV-2 antigens were produced (3 Mab anti-gag protein, 2 anti-env1, and 5 anti-env2). In the immunoblotting assay all the anti-gag Mabs reacted with HIV capsid protein p24, whereas one of them reacted also with p55 protein and with 7 other polypeptides. Another anti-gag Mab cross-reacted with the antigen of subpopulation of human peripheral blood lymphocytes. The third one interacted with the antigen of both HIV-1 and HIV-2. All the 10 Mabs interacted with natural HIV antigens and can be used for identification and differentiation of HIV-1 and HIV-2.

[The antiproliferative activity of monoclonal anti-idiotypic antibodies imitating the biological effects of human alpha-interferons]. / Antiproliferativnaia aktivnost' monoklonal'nykh antiidiotipicheskikh antitel, imitiruiushchikh biologicheskie éffekty chelovecheskikh interferonov al'fa.

The experimental data from the study of antiproliferative activity (AP-activity) of monoclonal antiidiotypic antibody (mono-Ai-At) imitating biological effects of human alpha interferons (h-IF-alpha) are presented. The mono-Ai-At present in the ascitic and culture fluids (the culture fluid was obtained from cultivation of hybrid cells immobilized in alginate-gelatine gel) were shown to inhibit propagation of IF-sensitive continuous cells from normal and tumor tissues. The AP-activity of mono-Ai-At was found to be within the range of their antiviral activity. It is concluded that mono-Ai-At may be used as a new experimental model for investigation of h-IF-alpha biological effects.

[Immunoenzyme test systems for detecting the HIV antigen and a trial of their use in examining HIV-infected subjects]. / Immunofermentnye test-sistemy dlia vyiavleniia antigena VICh i popytka ikh ispol'zovaniia pri obsledovanii VICh-infitsirovannykh lits.

The results of the development and trials of two variants of EIA test system for the detection of HIV-1 antigen using biotinated HIV-antibody and streptavidin-peroxidase or biotin-beta-lactamase enzyme complexes are presented. These diagnostic preparations proved to be highly sensitive and specific allowing the detection of the antigen in the blood of HIV-infected subjects.