Safety and Immunogenicity Study of a Bivalent Vaccine for Combined Prophylaxis of COVID-19 and Influenza in Non-Human Primates.

Background: Influenza and SARS-CoV-2 viruses are two highly variable pathogens. We have developed a candidate bivalent live vaccine based on the strain of licensed A/Leningrad/17-based cold-adapted live attenuated influenza vaccine (LAIV) of H3N2 subtype, which expressed SARS-CoV-2 immunogenic T-cell epitopes. A cassette encoding fragments of S and N proteins of SARS-CoV-2 was inserted into the influenza NA gene using the P2A autocleavage site.

A novel immunofluorescent test system for SARS-CoV-2 detection in infected cells.

Highly variable pandemic coronavirus SARS-CoV-2, which causes the hazardous COVID-19 infection, has been persistent in the human population since late 2019. A prompt assessment of individual and herd immunity against the infection can be accomplished by using rapid tests to determine antiviral antibody levels. The microneutralization assay (MN) is one of the most widely used diagnostic methods that has been proposed to assess the qualitative and quantitative characteristics of virus-specific humoral immunity in COVID-19 convalescents or vaccine recipients.

Expression of the SARS-CoV-2 receptor-binding domain by live attenuated influenza vaccine virus as a strategy for designing a bivalent vaccine against COVID-19 and influenza.

Influenza and SARS-CoV-2 are two major respiratory pathogens that cocirculate in humans and cause serious illness with the potential to exacerbate disease in the event of co-infection. To develop a bivalent vaccine, capable of protecting against both infections, we inserted the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein into hemagglutinin (HA) molecule or into the open reading frame of the truncated nonstructural protein 1 (NS1) of live attenuated influenza vaccine (LAIV) virus and assessed phenotypic characteristics of the rescued LAIV-RBD viruses, as well as their immunogenicity in mouse and Syrian hamster animal models. A panel of 9 recombinant LAIV-RBD viruses was rescued using the A/Leningrad/17 backbone.

Truncation of NS1 Protein Enhances T Cell-Mediated Cross-Protection of a Live Attenuated Influenza Vaccine Virus Expressing Wild-Type Nucleoprotein.

Current seasonal influenza vaccines have suboptimal effectiveness, especially in seasons dominated by viruses that do not match the vaccine. Therefore, finding new approaches to improve the immunogenicity and efficacy of traditional influenza vaccines is of high priority for public health. Licensed live attenuated influenza vaccine (LAIV) is a promising platform for designing broadly protective vaccines due to its ability to induce cross-reactive T-cell immunity.

Assessment of Immunogenic and Antigenic Properties of Recombinant Nucleocapsid Proteins of Five SARS-CoV-2 Variants in a Mouse Model.

COVID-19 cases caused by new variants of highly mutable SARS-CoV-2 continue to be identified worldwide. Effective control of the spread of new variants can be achieved through targeting of conserved viral epitopes. In this regard, the SARS-CoV-2 nucleocapsid (N) protein, which is much more conserved than the evolutionarily influenced spike protein (S), is a suitable antigen.

Development of a T Cell-Based COVID-19 Vaccine Using a Live Attenuated Influenza Vaccine Viral Vector.

The COVID-19 pandemic emerged in 2020 and has caused an unprecedented burden to all countries in the world. SARS-CoV-2 continues to circulate and antigenically evolve, enabling multiple reinfections. To address the issue of the virus antigenic variability, T cell-based vaccines are being developed, which are directed to more conserved viral epitopes.

Detection of IFNγ-Secreting CD4 and CD8 Memory T Cells in COVID-19 Convalescents after Stimulation of Peripheral Blood Mononuclear Cells with Live SARS-CoV-2.

Background: New coronavirus SARS-CoV-2, a causative agent of the COVID-19 pandemic, has been circulating among humans since November 2019. Multiple studies have assessed the qualitative and quantitative characteristics of virus-specific immunity in COVID-19 convalescents, however, some aspects of the development of memory T-cell responses after natural SARS-CoV-2 infection remain uncovered.

Methods: In most of published studies T-cell immunity to the new coronavirus is assessed using peptides corresponding to SARS-CoV-1 or SARS-CoV-2 T-cell epitopes, or with peptide pools covering various parts of the viral proteins.

Influenza vaccine: progress in a vaccine that elicits a broad immune response.

Introduction: The licensed seasonal influenza vaccines predominantly induce neutralizing antibodies against immunodominant hypervariable epitopes of viral surface proteins, with limited protection against antigenically distant influenza viruses. Strategies have been developed to improve vaccines' performance in terms of broadly reactive and long-lasting immune response induction.

Areas Covered: We have summarized the advancements in the development of cross-protective influenza vaccines and discussed the challenges in evaluating them in preclinical and clinical trials.

Conserved T-cell epitopes of respiratory syncytial virus (RSV) delivered by recombinant live attenuated influenza vaccine viruses efficiently induce RSV-specific lung-localized memory T cells and augment influenza-specific resident memory T-cell responses.

Respiratory syncytial virus (RSV) can cause recurrent infection in people because it does not stimulate a long-lived immunological memory. There is an urgent need to develop a safe and efficacious vaccine against RSV that would induce immunological memory without causing immunopathology following natural RSV infection. We have previously generated two recombinant live attenuated influenza vaccine (LAIV) viruses that encode immunodominant T-cell epitopes of RSV M2 protein in the neuraminidase or NS1 genes.

Recombinant Live Attenuated Influenza Vaccine Viruses Carrying Conserved T-cell Epitopes of Human Adenoviruses Induce Functional Cytotoxic T-Cell Responses and Protect Mice against Both Infections.

Human adenoviruses (AdVs) are one of the most common causes of acute respiratory viral infections worldwide. Multiple AdV serotypes with low cross-reactivity circulate in the human population, making the development of an effective vaccine very challenging. In the current study, we designed a cross-reactive AdV vaccine based on the T-cell epitopes conserved among various AdV serotypes, which were inserted into the genome of a licensed cold-adapted live attenuated influenza vaccine (LAIV) backbone.

Live attenuated influenza vaccine viral vector induces functional cytotoxic T-cell immune response against foreign CD8+ T-cell epitopes inserted into NA and NS1 genes using the 2A self-cleavage site.

The development of viral vector vaccines against various pathogens for which conventional vaccination approaches are not applicable has been a priority for a number of years. One promising approach is the insertion of immunodominant conservative cytotoxic T-cell (CTL) epitopes into the genome of a viral vector, which then delivers these epitopes to target cells, inducing immunity. Many different viruses have been assessed as viral vectors for CTL-based vaccines, but only a few of them are clinically relevant, mainly because of safety issues and limited knowledge about their performance in humans.

Recombinant N-Domain of Pregnancy-Specific Glycoprotein from E. coli Cells: Analysis of the Spectrum of Polyclonal Antibodies.

We studied antibody spectrum in antisera to IgG-like recombinant N-domain of pregnancyspecific glycoprotein-1 (rPSG-N) from E. coli cells. In three experimental series, the fraction of IgG antibodies from anti-rPSG-N sera was immobilized on 3 immunoadsorbents: by polymerization with glutaraldehyde, on glutaraldehyde activated biogel P-300, and on commercial CNBr-activated 4B sepharose.

Serum IgG-like glycoferroprotein: identification of its final dissociation form of thermostable protein coupled with albumin.

Human serum IgG-like glycoferroprotein identical to ascitic IgG-like glycoferroprotein that binds labeled monoclonal antibodies to CA125 is a complex consisting of three proteins: IgG, human serum albumin, and unidentified thermostable protein. Final dissociation form of serum IgG-like glycoferroprotein also appears as a complex of three nonidentical polypeptides with a molecular weight of 55 kDa (PC55) migrating in the albumin zone of thermostable protein coupled with albumin and structures chemically identical to human serum albumin and IgG heavy chains. Under denaturing conditions of electrophoresis in polyacrylamide gel, IgG-like glycoferroprotein and PC55 have the same molecular weight (about 55 kDa), while under reducing conditions their weight is about 75 kDa.

Identification and characterization of serum protein in patients with ovarian cancer.

A 36 kDa protein was isolated from the sera of patients with ovarian cancer and rabbit antisera to this protein were prepared. Precipitation test with these antisera detected an antigen with electrophoretic mobility corresponding to alpha-1-globulins and molecular weight of 36 kDa. Direct comparison of precipitating test systems showed that this antigen is not identical to the known carcinoembryonic, placental, and reactive proteins.

Hyperfine interactions in the iron cores from various pharmaceutically important iron-dextran complexes and human ferritin: a comparative study by Mössbauer spectroscopy.

Mössbauer spectroscopy has been used to study the hyperfine interactions in the iron cores of pharmaceutically important industrial and elaborated iron-dextran complexes (ferritin models) and human ferritin. Mössbauer spectra of frozen solutions and lyophilized samples of iron-dextran complexes at 87 K demonstrated magnetic, superparamagnetic and paramagnetic states of iron in various complexes. Mössbauer spectra of human ferritin in frozen solution and lyophilized form showed paramagnetic state of iron at 87 K.

Antigenic structure of ovarian cancer metastases.

Twenty highly specific (organ-specific and tumor-associated) antigens named ovarian metastatic antigens were revealed using polyclonal antibodies isolated from rabbits after immunization with soluble antigens from ovarian cancer metastases. These protein antigens were not detected by precipitating test system (sensitivity 1 mg/liter) in tissues of adult humans (except for organ-specific antigens) and blood plasma from healthy donors. Ovarian metastatic antigens included organ-specific, placenta-specific, tumor embryonic, tumor-associated, and reactive proteins.

[Effect of imipramine and ftoracizin on platelet aggregation and smooth muscle contraction of the ureter].

The influence of the tricyclic antidepressants imipramine and ftoracizin on platelet aggregation and smooth muscle contractility was investigated in comparison with action of known smooth muscle relaxant and platelet aggregation inhibitor, papaverine. It has been shown that the tricyclic antidepressants possess potent spasmolytic activity but unlike papaverine have no effect on platelet aggregation. The biochemical mechanisms of the non-specific action of tricyclic antidepressants as well as some other structurally related-drugs are discussed.

[Immunochemical identification of onco-ovarian acid-soluble alpha-2-globulin].

Antisera were obtained by rabbits immunization with pooled extract from ovarian carcinoma and its metastases into the ome tum. Using standard test-system antigen, precipitating in agar, was identified in the tissue of 12 out of 24 primary ovarian carcinomas and in 8 out of 20 metastases. It was not revealed in adult healthy internal organs tissues and in fetal tissues, except embryonal large intestine, where it was determined in trace amounts in isolated samples.

[Immunoenzyme analysis of ovarian metastatic antigen-8].

Immunoenzymatic method for the determination of new ovarian-metastatic antigen-8 in human blood serum was worked out. OMA-8 level was studied in blood serum of 40 healthy women, 40 healthy men, 16 neonates, 33 pregnant women, 103 patients with genital tumours. It was found out that OMA-8 level in blood serum of healthy women changed between 2 to 15.

[Detection of trophoblastic beta 1-glycoprotein in tumor tissue and blood in ovarian neoplasms].

Using immunochemical analysis methods (the reaction of precipitation in agar, immunoenzymatic method, immunofluorescence), trophoblastic beta 1-glycoprotein (TBG) concentration in tumour tissue and in the blood serum of patients with ovarian cancer was studied. By rabbits immunization with glycoprotein fraction of ovarian adenocarcinoma, dissolved in 0.6 M sulfosalicylic acid, the authors obtained antibodies to TBG.

[Ovarian metastatic antigen in the blood serum of patients with ovarian tumors].

Enzyme immunoassays of ovarian metastatic antigen 8 (OMA-8) in sera of patients with ovarian cancer have shown its elevation in 74.5% of samples. OMA-8 levels did not correlate with histology, differentiation, clinical stage of the tumour or the presence of ascites.

[Serum ferritin and trophoblastic globulin in genital tumors in women].

Blood serum levels of ferritin and trophoblastic globulin were measured by immunoassay in 389 and 114 cases, respectively, suffering malignant or benign tumors of the uterus and ovary as well as in controls. Hyperferritinemia identified at serum ferritin levels in excess of 200 micrograms/l was established in 94% of cases of ovarian cancer, 57%--benign ovarian tumors, 60%--endometrial carcinoma and in 16% of patients with uterine myoma. Patients with ovarian and uterine malignancies were shown to have the highest serum ferritin levels.

[Immunochemical identification of beta2-globulin in metastases of ovarian tumors].

Antisera were obtained upon immunization of rabbits with the extracts obtained from metastatic tissues of primary ovarian carcinoma into the omentum. Eight antigens were found, which were termed "ovarian-metastatic antigens" (OMA). OMA 1-7 showed cross-reactions with the antigens of one of the normal organs of the adult man: kidneys, spleen, brain.

[Distribution of cytoplasmic ferroproteins and iron in human kidney tumors].

Using immuno- and histochemical techniques, it has been shown that the primary tumoural node in kidney cancer is a locus with an extraordinarily high concentration of cytoplasmic ferroproteins and ferrum (Fe3+). Fe3+ is located in the cytoplasm of nephrothelium of tumour-affected kidney tubules, intensively incrustates the cell cytoplasm in the primary tumoural node and is revealed in separate nuclei of the primary node cells. Possible consequences of high local ferrum concentration in cells is discussed.