Analysis of the Frequency of Mutations at Diagnostic Oligonucleotide Sites and Their Impact on the Efficiency of PCR for HIV-1.

The development of effective diagnostic kits for HIV-1 remains a pressing concern. We designed diagnostic oligonucleotides for HIV-1 real-time PCR to target the most conserved region of the HIV-1 genome and assessed the mutation frequency at annealing sites. Two databases of nucleotide sequences, Los Alamos and NCBI, were analyzed, revealing that more than 99% of the sequences either lack mutations or contain 1-2 mutations at the binding site of the forward and reverse primers. Additionally, 98.5% of the sequences either lack mutations or contain 1-2 mutations at the binding site of the TaqMan probe. To evaluate the efficiency of primers and the probe in real-time PCR in the case of mutations at their binding sites, we constructed several plasmids containing the most common mutations and, in a model experiment, showed how different mutations affect the efficiency of PCR. Our analysis demonstrated that about 98.5% of HIV-1 strains can be efficiently detected using a single pair of selected primers. For the remaining 1.5% of strains, a more careful selection of the second target is needed.

Development of MVA-d34 Tetravalent Dengue Vaccine: Design and Immunogenicity.

Dengue fever, an infectious disease that affects more than 100 million people every year, is a global health problem. Vaccination may be the most effective prevention strategy for the disease. However, the development of vaccines against dengue fever is complicated by the high risk of developing an antibody-dependent increase in infection. This article describes the development of an MVA-d34 vaccine against the dengue virus based on a safe and effective MVA viral vector. The DIII domains of the envelope protein (E) of the dengue virus are used as vaccine antigens, as antibodies against these domains do not cause an enhancement of infection. The use of the DIII domains of each of the four dengue virus serotypes made it possible to generate a humoral response against all four dengue virus serotypes in immunized mice. We also showed that the sera of vaccinated mice present virus-neutralizing activity against dengue serotype 2. Thus, the developed MVA-d34 vaccine is a promising candidate vaccine against dengue fever.

Double and Triple Combinations of Broadly Neutralizing Antibodies Provide Efficient Neutralization of All HIV-1 Strains from the Global Panel.

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.

Development of a Universal Epitope-Based Influenza Vaccine and Evaluation of Its Effectiveness in Mice.

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.

Comparison of Recombinant MVA Selection Methods Based on F13L, D4R and K1L Genes.

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.