F. Gamaleya Federal Research Center for Epidemiology & Microbiology, is a Russian medical-research institute within the Ministry of Health of the Russian Federation.[note 2]Founded in 1891 by Filipp Markovich Blyumental, it is named after Ukrainian-born Soviet scientist Nikolay Fyodorovich Gamaleya (1859–1949), famed as a pioneer in microbiology and in vaccine research. The institute is best known internationally for developing the earliest vaccine for SARS-CoV-2, in collaboration with the 48th Central Research Institute of the Ministry of Defence and the Vector Institute of the Rospotrebnadzor, in response to the COVID-19 pandemic.
The effect of SARS-CoV-2 inactivation has been established in the wavelength range of 343 to 401 nm. The results of determining the spectral sensitivity and threshold cycle for RNA fragments of SARS-CoV-2, when exposed to radiation in the human-safe UVA range, are presented. The findings can be used to create human-safe sources of virus eradication in public places.
Background/Objectives: A key disadvantage of DNA vaccines is ineffective uptake of plasmid DNA, resulting in low immunogenicity. A way to overcome it is forced DNA delivery, which requires specialized equipment and/or reagents. Effective delivery of plasmids without specialized devices or using commonly available ones would significantly increase DNA vaccine applicability. Here, we delivered DNA by intradermal injections, facilitating them by optimized sonoporation (SP) or electroporation (EP), and we compared these methods by their capacity to support the production of foreign proteins in mice. Methods: DNA delivery was optimized using the plasmid encoding firefly luciferase (Luc) (pVaxLuc). Luc production was assessed by bioluminescence imaging (BLI) (IVIS, PerkinElmer, Shelton, CT, USA; LumoTrace Fluo, Abisense, Dolgoprudny, Russia). Female BALB/c mice were injected intradermally (id) with pVaxLuc in phosphate buffers of varying ionic strengths. Injection sites were subjected to SP (Intelect Mobile, Chattanooga, UK) or EP (CUY21EDITII, BEX Co., Tokyo, Japan) or left untreated. Optimal delivery protocols were selected based on the highest in vivo levels of photon flux according to BLI. Optimal protocols for id injections with/without EP were applied to DNA-immunized mice with HIV-1 clade A reverse transcriptase. Antibody response induced by DNA immunization was assessed by ELISA. Results: The optimal phosphate buffers for id delivery had ionic strengths from 81 to 163 mmol/L. The optimal SP regimen included an acoustic pressure of 2.4 W/cm2 applied in a duty cycle of 2%. The optimal EP regimen included bipolar driving pulses of 100 V, a pulse duration of 10 ms, and an interval between the pulses of 20 ms. Optimized DNA delivery by id/SP injection was inferior to both id/EP and id alone. DNA immunization with HIV-1 RT by id injections induced anti-RT antibodies in a titer of 104 and by id/EP in a titer of 105. Conclusions: Electroporation of the sites of id DNA injection provided the highest levels of production of luciferase reporters and induced a strong antibody response against HIV-1 RT.
Aim. To study the effect of storage temperatures (-20 and -70 оC) and exposure duration (6 months and 6 years) on the preservation and stability of specific anti-hepatitis B virus HBs antigen IgG antibodies (anti-HBs IgG) in serum samples stored in a biobank. Material and methods . An experimental study was conducted on 180 serum samples. Anti-HBs IgG levels were determined by enzyme-linked immunosorbent assay (ELISA) using Vector-Best test systems (Russia) in native samples and after storage according to two following scenarios: 1) storage at -20 and -70 оC for 6 months; 2) storage at -70 оC for 6 months and 6 years. Statistical analysis was performed using nonparametric methods (Wilcoxon test, median, interquartile range, Spearman correlation coefficient). Results . The study using the first scenario found that storage at -20 оC for 6 months led to an almost 2-fold increase in the median anti-HBs IgG level (from 35,5 (7,8-76,8) to 65,3 (26,0-105,0) IU/ml) and 9 false-positive results. In the second scenario study, storage at -70 оC for 6 months was accompanied by a slight decrease in antibody levels (from 72,5 (27,9-132,0) to 49,3 (4,0-98,4) IU/ml) without false positive results. After 6 years of storage at -70 оC, a further decrease to 33,3 (6,15-88,4) IU/ml was noted, with 2 samples becoming false negative. A strong correlation was found between antibody levels in native samples and after storage (р=0,97-0,99; p<0,05). Conclusion . Long-term (up to 6 years) storage of serum samples at -70 оC is reliable and does not critically distort the results of population serological studies of anti-HBs IgG prevalence. Storage at -20 оC is only acceptable for short-term storage, as after just 6 months it leads to false-positive results and an overestimation of the average antibody level, making it unsuitable for biobanking.
Vif and Vpr are HIV-1 accessory proteins that create optimal conditions for viral replication. They are considered as potential targets for the development of therapeutic agents. Natural amino acid substitutions in these proteins have previously been associated with disease progression. The aim of this study was to analyze the genetic diversity of Vif and Vpr in HIV-1 group M clades. A total of 5286 sequences were downloaded and analyzed. For 37 clades in group M, the consensus sequences, amino acid natural variation, and clade-specific amino acid residue substitutions (CSSs) were evaluated. Structural analysis and modeling of consensus sequences were performed for subtypes A1, B, C, and D. The average conservation degree in the HIV-1 group M was 86.4% for Vif and 91.3% for Vpr. In both proteins, the lowest amino acid diversity was observed in sub-subtype A6, and the highest in subtype B. In consensus sequences, the substitutions, which might influence pathogenesis, have been determined: in Vif—22H (11_cpx, 91_cpx) and 136P (A6, 01_AE, 15_01B, 59_01B, 89_BF1, 103_01B, 111_01C, 133_A6B), in Vpr—41N (06_cpx) and 55A (B, 07_BC, 35_01D, 56_cpx, 66_cpx, 66_BF1, 71_BF1, 85_BC, 137_0107). In functional motifs, CSSs associated with changes in the chemical properties of amino acid residues were noted. These findings could be taken into account for the development of therapeutic drugs in the future. No correlation was observed between the subtypes and the spatial organization of the oligomeric structures of Vif and Vpr. Using the structural analysis and modeling, it has been shown for the first time that Vif can interact with APOBEC3G as an oligomer.
Background/Objectives: While tick-borne encephalitis virus (TBEV) is genetically relatively conserved, the significant antigenic divergence between its main circulating subtypes hinders the development of broadly effective antiviral treatments and vaccines. Current inactivated TBEV vaccines offer limited cross-protection against heterologous strains, as evidenced by cases among vaccinated individuals in endemic regions. The aim of this study was to design a candidate mRNA vaccine and evaluate the breadth of protective immunity it elicits. Methods: Ten candidate mRNA-PrM/E-LNP vaccines were comparatively evaluated for immunogenicity and protective efficacy in BALB/c mice. Immunogenicity was assessed by measuring antigen-specific IgG titers via ELISA and neutralizing antibody titers against a panel of TBEV strains using a virus-neutralization test. Protective efficiency was determined in a lethal challenge model, where immunized mice were challenged with one of seven distinct TBEV strains. Results: Vaccination with all tested mRNA-PrM/E-LNP candidates conferred 100% survival in mice following a lethal challenge with each of the seven TBEV strains (100 LD50). The construct mRNA-PrM/E—Krasny Yar-8 demonstrated the highest immunogenicity, inducing antigen-specific antibodies with a geometric mean titer (GMT) of 1:6625, as well as the broadest virus-neutralizing activity against both homologous and heterologous TBEV strains in vitro. Conclusions: The mRNA platform represents a promising strategy for developing TBEV vaccines, demonstrating high immunogenicity and cross-protective efficacy against diverse viral strains.
