Dina Viktorovna Glazkova

INTRODUCTION. Despite existing treatment methods, complete eradication of human immunodeficiency virus (HIV) infection remains an unattainable goal due to the high variability of HIV type 1 (HIV-1). HIV infection necessitates life-long administration of antiretroviral medicinal products, which cause serious adverse drug reactions. The development of gene therapy products based on adeno-associated virus (AAV) vectors encoding broadly neutralising antibodies represents a promising direction for creating long-term therapies capable of countering a wide range of viral variants.AIM. This study aimed to evaluate the protective efficacy of CombiMab-2, a medicinal product consisting of a combination of three AAV vectors (AAV9-VRC07-523, AAV9-10-1074, and AAV9-PGDM1400) encoding broadly neutralising antibodies against HIV-1, in a humanised mouse model.MATERIALS AND METHODS. The study used an HIV infection model based on immunodeficient B-NDG mice humanised with human CD4⁺ lymphocytes (1.5×10⁷ cells per animal) from a leukoconcentrate of a healthy donor. The experiment used two groups of mice, including a control group (3 animals) receiving saline solution and an experimental group (5 animals) receiving CombiMab-2. The medicinal product was administered into different muscles as three separate components six weeks prior to infection. The CCR5-tropic HIV-1 strain was obtained by transfecting HEK293FT cells with the pNL4-3(AD8) plasmid encoding the full-length virus. The authors monitored viral loads in the plasma of animals by reverse transcription polymerase chain reaction and CD4⁺ lymphocyte counts in the peripheral blood of animals by flow cytometry for four weeks after infection.RESULTS. Six weeks after CombiMab-2 administration, the levels of broadly neutralising antibodies in the serum of humanised mice ranged from 0.17 μg/mL to 4.0 μg/mL. In the control group, the viral load reached 10⁵ copies/mL one week after HIV-1 infection and continued to rise over the next three weeks. In the treatment group, infection developed only in one mouse, which had the lowest antibody titre before infection. No viral load was detected in the remaining mice of the treatment group, which indicated that the medicinal product was effective if serum concentrations of broadly neutralising antibodies reached 0.5 μg/mL or higher.CONCLUSIONS. The tested medicinal product based on three AAV vectors (AAV9-VRC07-523, AAV9-10-1074, and AAV9-PGDM1400) exhibits protective activity against HIV-1 in humanised mice. The presented data allow the authors to consider CombiMab-2 as a promising antiviral agent that can serve as a basis for further pharmaceutical development.

Anti-human immunodeficiency virus (HIV) broadly neutralizing antibodies (bNAbs) offer a promising approach for the treatment of HIV-1. The current paradigm for antibody therapy involves passive antibody transfer, requiring regular delivery of bNAbs in treating chronic diseases such as HIV-1. An alternative strategy is to use AAV-mediated gene transfer to enable in vivo production of desirable anti-HIV-1 antibodies. In this study, we investigated two sets of triple combinations of AAV9-vectors encoding different bNAbs: N6, 10E8, 10-1074 (CombiMab1), and VRC07-523, PGDM1400, 10-1074 (CombiMab2). We used CBAxC57Bl and C57BL/6 mouse models to characterize rAAV-induced antibody expression and to evaluate the neutralization capacity of mouse sera against a global panel of HIV-1 viral strains. rAAV9-mediated IgG expression varied between bNAb clones and mouse strains, with C57BL/6 mice exhibiting higher bNAb titers following rAAV delivery. Although CombiMab2 treatment elicited a higher IgG titer than CombiMab1, both combinations resulted in neutralization of all the viral strains from the global HIV-1 panel. Our data highlight the potential of AAV vectors as a long-term option for HIV-1 therapy.

A promising direction in the treatment of HIV infection is a gene therapy approach based on the insertion of antiviral genes aimed at inhibiting HIV replication into the genome of host cells. We obtained six constructs of lentiviral vectors with different arrangements of three antiviral genes: microRNAs against the CCR5 gene, the gene encoding the C-peptide, and the gene encoding the modified human TRIM5a protein. We found that despite containing the same genes, these vectors were produced at different titers and had different effects on cell viability, transduction efficiency, and expression stability. Comparative evaluation of the antiviral activity of three of the six developed vectors that showed stable expression was carried out using the continuous SupT1 lymphocytic cell line. All of the vectors protected cells from HIV infection: the viral load was several orders of magnitude lower than in control cells, and with one vector, complete cessation of virus growth in modified cells was achieved.

Modified vaccinia virus Ankara (MVA) is a promising viral vector for vaccine development. MVA is well studied and has been widely used for vaccination against smallpox in Germany. This review describes the history of the origin of the virus and its properties as a vaccine, including a high safety profile. In recent years, MVA has found its place as a vector for the creation of vaccines against various diseases. To date, a large number of vaccine candidates based on the MVA vector have already been developed, many of which have been tested in preclinical and clinical studies. We discuss data on the immunogenicity and efficacy of some of these vaccines.

The use of broadly neutralizing antibodies (bNAbs) is a promising approach to HIV-1 treatment. In this work, we evaluate the neutralizing activity of the following HIV-1 bNAbs: VCR07-523, N6, PGDM1400, CAP256-VRC26.25, 10-1074, PGT128, 10E8, and DH511.11P, which are directed to different Env surface epitopes. We used the global panel of HIV-1 pseudoviruses to analyze the bNAbs’ potency and chose the most potent ones. To achieve maximum neutralization breadth and minimum IC₅₀ concentration, the most effective antibodies were tested in double and triple combinations. Among the doubles, the combinations of N6+PGDM1400 and N6+PGT128 with IC₅₀ ≤ 0.3 µg/mL proved to be the most effective. The most effective triple combination was N6+PGDM1400+PGT128. Our data demonstrate that this combination neutralizes pseudoviruses of the global HIV-1 panel with IC₅₀ ≤ 0.11 µg/mL and IC₈₀ ≤ 0.25 µg/mL.

Vaccination is an effective and economically viable means of protection against the influenza virus, but due to rapid viral evolution, modern seasonal vaccines are not effective enough. Next-generation vaccines are designed to provide protection against a wide range of influenza virus strains, including pandemic variants. In our work, we made an epitope-based universal vaccine, rMVA-k1-k2, against the influenza virus based on the modified vaccinia Ankara (MVA) vector and using our own algorithms to select epitopes from conserved fragments of the NP, M1 and HA proteins of influenza A and B. We show that double immunization protects mice with a 67% or greater efficiency against viral influenza pneumonia when infected with various strains of the H1N1, H2N2, H3N2 and H5N1 subtypes of influenza A. In animals, the level of protection provided by the rMVA-k1-k2 vaccine was comparable to that provided by the universal M001 and MVA-NP+M1 (Invictus) vaccines, which have shown success in clinical trials, against strains of the H1N1 and H3N2 subtypes.

Modified vaccinia Ankara (MVA) is a promising vaccine vector due to its highly attenuated phenotype and good immunogenicity. However, obtaining a new recombinant MVA remains a tedious and laborious procedure involving many rounds of plaque purification. Recombinant MVA generation can be greatly improved and facilitated by different selection techniques. Here, we describe a comparison between techniques based on K1L, F13L and D4R genes.

Antibodies with neutralizing activity against a wide range of human immunodeficiency virus 1 subtypes (known as broadly neutralizing antibodies — bNAb) are of great interest as a therapeutic agent for the treatment of HIV infection, because they are able to provide natural protection against most HIV-1 strains. The review discusses the mechanisms of formation of bNAbs, their classification by binding to conservative regions of the envelope protein, as well as their intrinsic features. Description of the most promising bNAbs and their combinations is presented.In the last section the results of clinical trials of 3BNC117, VRC01 and 10-1074 bNAbs available to date are reviewed in detail. An important finding of these studies was that the introduction of a single antibody is followed by the appearance of resistant viral variants. The investigation of the only combination of 3BNC117 and 10-1074 completed so far indicates that combined therapy is more effective and allows to achieve long-term viral suppression in some patients. The promise of combined HIV immunotherapy is evidenced by the initiation of a large number of clinical trials evaluating the efficacy of two or more different bNAbs.

Current methods of HIV treatment can contain a progression of the disease; however they do not lead to a cure. Lifelong antiretroviral therapy is therefore necessary, leading to problems of cost and toxicity of chemical drugs. The recent advances in science have allowed a new approach to the HIV-treatment — gene therapy. In the present publication we focus on one strategy of the gene therapy called «intracellular immunization». The strategy is based on the introducing of antiviral genes into the HIV-sensitive cells. We highlight the mechanisms of action of various antiviral genetic agents and discuss some issues concerning target cells and genes delivery. Finally we summarize the results of certain gene therapy clinical trials.