Immunogenic Properties of MVs Containing Structural Hantaviral Proteins: An Original Study

Hemorrhagic fever with renal syndrome (HFRS) is an emerging infectious disease that remains a global public health threat. The highest incidence rate is among zoonotic disease cases in Russia. Most cases of HFRS are reported in the Volga region of Russia, which commonly identifies the Puumala virus (PUUV) as a pathogen. HFRS management is especially challenging due to the lack of specific treatments and vaccines. This study aims to develop new approaches for HFRS prevention. Our goal is to test the efficacy of microvesicles (MVs) as PUUV nucleocapsid (N) and glycoproteins (Gn/Gc) delivery vehicles. Our findings show that MVs could deliver the PUUV N and Gn/Gc proteins in vitro. We have also demonstrated that MVs loaded with PUUV proteins could elicit a specific humoral and cellular immune response in vivo. These data suggest that an MV-based vaccine could control HFRS.

IMMUNOGRAPH-BASED ANALYSIS OF THE INFLUENZA A (H1N1)PDM09 VACCINE STRAIN IMMUNOGENICITY IN THE PANDEMIC AND POST-PANDEMIC PERIOD (2009-2014)

Currently, the assessment of the immunogenic properties of influenza viruses as a part of influenza vaccines, is carried out by using seroprotection, seroconversion as well as the rate of increases in post-vaccination antibodies. At the same time, significant differences in the immunogenicity of vaccines related to dynamic formation of high antibody titers responsible for long-term protection of the vaccinated, are neglected.Influenza viruses such as A (H1N1) pdm09 that caused 2009-2010 pandemic continue to circulate in the population, therefore, the assessment of the immunogenic activity of vaccine viruses prepared during the pandemic period is interesting in for the methodology to prepare pandemic vaccines to be used in various groups (adults, children, elderly people).Analyzing immunogenicity of influenza vaccines used during the 2009-10 swine influenza pandemic and the post-pandemic period up to the year 2014 was carried out by applying the graphical method for assessing immunogenicity (immunographs) measured as follows: for each group of vaccinated subjects (depending on the vaccine used), an increased rate in antibody level was calculated and the graphs of immunogenicity were plotted. An increased rate of serum antibodies magnitude from vaccinated subjects and the number of sera (in%) with a given fold increase rate in antibody level from 1 to the maximum magnitude were plotted on the x- and y-axis, respectively. The proposed method for assessing immunogenicity allows to plot immunogenicity graphs regardless of the serum antibodies level found in volunteers. The assessment described above revealed a several features for developing immune response to the pandemic virus A (H1N1)pdm09 such as the lack of immune response in a substantial number of adult volunteers (25-27%%) and young children (60-70%%) after monovaccine administration. The reason for such immune response can be both an insufficient dose of vaccine-containing viral antigen and suppressed immune response caused by the influenza A(H1N1)pdm09.A study on the immunogenic properties for seasonal influenza vaccines containing the influenza A (H1N1) pdm09 virus antigen in the years 2010 - 2014 revealed a variety in emerging humoral immunity ranging from a short-term, low-frequency increase in antibodies from vaccinated children to the formation of high antibody titers in elderly.Practically, immunographic analysis of influenza vaccines particularly those derived from the influenza A (H1N1)pdm09 virus, may result in proposing recommendations to increase an antigenic load at the beginning of a pandemic cycle and/or block the suppressive properties of vaccine-contained viruses in pediatric vaccines, because escalating virus dose in the vaccine may not always be achievable in this case.

Preparation, Characterization and Preliminary in vivo Testing of Liposomated Antiidiotypic Antibodies Against Morphine Derivatives

Artificial membrane structures containing medicinal substances are highly promising for the development of new drugs. Liposomal preparations are actively used in medical practice due to their high efficacy and relatively low toxicity. Our aim was to encapsulate anti-idiotypic antibodies into a liposomal composition with the purpose of improving their immunogenic properties. Following the preparation of a liposomal composition by the dehydration/rehydration method using ultrasonic treatment, the size, zeta potential, and loading efficiency of liposomes were investigated. Preliminary in vivo studies were conducted to evaluate the adjuvant properties of liposomes of varying size. Loaded liposomes of the smallest diameter (about 110 nm) showed the potential of enhancing the immune response similar to that obtained using Freund’s adjuvant. These results justify further research into the properties of liposomes loaded with antibodies.

Wheat Breeding, Fertilizers, and Pesticides: Do They Contribute to the Increasing Immunogenic Properties of Modern Wheat?

Celiac disease (CD) is a small intestinal inflammatory condition where consumption of gluten induces a T-cell mediated immune response that damages the intestinal mucosa in susceptible individuals. CD affects at least 1% of the world’s population. The increasing prevalence of CD has been reported over the last few decades. However, the reason for this increase is not known so far. Certain factors such as increase in awareness and the development of advanced and highly sensitive diagnostic screening markers are considered significant factors for this increase. Wheat breeding strategies, fertilizers, and pesticides, particularly herbicides, are also thought to have a role in the increasing prevalence. However, less is known about this issue. In this review, we investigated the role of these agronomic practices in depth. Our literature-based results showed that wheat breeding, use of nitrogen-based fertilizers, and herbicides cannot be solely responsible for the increase in celiac prevalence. However, applying nitrogen fertilizers is associated with an increase in gluten in wheat, which increases the risk of developing celiac-specific symptoms in gluten-sensitive individuals. Additionally, clustered regularly interspaced short palindromic repeats (CRISPR) techniques can edit multiple gliadin genes, resulting in a low-immunogenic wheat variety that is safe for such individuals.

Activation of anti-SARS-CoV-2 human CTLs by extracellular vesicles engineered with the N viral protein

We investigated an innovative anti-SARS-CoV-2 immune strategy finalized to oral administration of extracellular vesicles (EVs) inducing an anti-SARS-CoV-2 N CD8+ T cytotoxic lymphocyte (CTL) immune response. We previously reported that the SARS-CoV-2 N protein can be uploaded at high levels in EVs upon fusion with Nefmut, i.e., a biologically inactive HIV-1 Nef mutant incorporating into EVs at quite high levels. Here, we analyze the immunogenic properties in human cells of EVs engineered with SARS-CoV-2 N fused at the C-terminus of either Nefmut or a deletion mutant of Nefmut referred to as NefmutPL. Analysis of in vitro produced EVs proven the uploading of N protein also when fused with truncated Nefmut. Mice injected with DNA vectors expressing each fusion protein developed robust SARS-CoV-2 N-specific CD8+ T cell immune responses. When ex vivo human dendritic cells were challenged with EVs engineered with either fusion products, the induction of a robust N-specific CTL activity, as evaluated by both CD107a and trogocytosis assays, was observed. Through these data we achieved the proof-of-principle that engineered EVs can be instrumental to elicit anti-SARS-CoV-2 CTL immune response in human cells. This achievement represents a mandatory step towards the upcoming experimentations in pre-clinical models.

Immunogenic properties of the preparation containing the Chikungunya virus antigen inactivated by β-propiolactone

Introduction. Cases of Chikungunya fever have been reported in more than 100 countries in Europe, Oceania, Africa, Asia, the Caribbean, and America. The musculoskeletal disorders typical for Chikungunya fever can last from several months to a year and even lead to disability. The infection is believed to provide lifelong immunity. This factor and the lack of specific therapy make vaccination the most promising method for preventing Chikungunya fever.Materials and methods. The purified inactivated preparation with the different doses of the CHIKV antigen was injected intramuscularly to BALB/c mice twice with an interval of 14 days. Indicators of humoral and cellular immunity were assessed in dynamics in ELISA, the neutralization test and proliferation test of splenocytes. Results. The purified preparation containing the CHIKV antigen inactivated by beta-propiolactone had pronounced immunogenic properties. The most prominent immune response in ELISA and neutralization test was registered for a dose of 40 μg. Stimulation with the specific CHIKV antigen caused a pronounced proliferation of animals' splenocytes. The peak values of specific humoral and cellular immunity parameters were registered 14 days after the second injection.Discussion. The purified preparation containing the CHIKV antigen inactivated by beta-propiolactone had demonstrated the sufficient immunogenic properties. The immunizing dose of 40 μg CHIKV selected as a result of the studies caused in BALB/c mice the development of the humoral immunity characterized by the specific IgG with neutralizing activity, and the specific cell immunity characterized by the animals' splenocytes proliferation after stimulation with CHIKV antigen.Conclusion. The purified β-PL inactivated preparation of the CHIKV antigen at a dose of 40 μg to demonstrated pronounced immunogenicity in BALB/c mice after two-dose immunization. The developed preparation can be considered as promising for the prevention of Chikungunya fever using the dose and scheme tested in this study.

Spatial dynamics and vaccine-induced fitness changes of Bordetella pertussis

Competitive interactions between pathogen strains drive infection risk. Vaccines are thought to perturb strain diversity through shifts in immune pressures, however, this has rarely been measured due to inadequate data and analytical tools. Bordetella pertussis (B. pertussis), responsible for 160,000 deaths annually, provides a rare natural experiment as many countries have switched from whole cell vaccines to acellular vaccines, which have very different immunogenic properties. Here we use 3,344 sequences from 23 countries and build phylogenetic models to reveal that B. pertussis has substantial diversity within communities, with the relative fitness of local genotypes changing in response to switches in vaccine policy. We demonstrate that the number of transmission chains circulating within subnational regions is strongly associated with host population size. It takes 5-10 years for individual lineages to be homogeneously distributed throughout Europe or the United States. Increased fitness of pertactin-deficient strains following implementation of acellular vaccines, but reduced fitness otherwise, can explain long-term genotype dynamics. These findings highlight the role of national vaccine policies in shifting local diversity of a pathogen that still poses a large burden on global public health.

A Bioinformatics Approach for the Prediction of Immunogenic Properties and Structure of the SARS-COV-2 B.1.617.1 Variant Spike Protein

Background. B.1.617.1, a variant of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) causing respiratory illness is responsible for the second wave of COVID-19 and associated with a high incidence of infectivity and mortality. To mitigate the B.1.617.1 variant of SARS-CoV-2, deciphering the protein structure and immunological responses by employing bioinformatics tools for data mining and analysis is pivotal. Objectives. Here, an in silico approach was employed for deciphering the structure and immune function of the subunit of spike (S) protein of SARS-CoV-2 B.1.617.1 variant. Methods. The partial amino acid sequence of SARS-CoV-2 B.1.617.1 variant S protein was analyzed, and its putative secondary and tertiary structure was predicted. Immunogenic analyses including B- and T-cell epitopes, interferon-gamma (IFN-γ) response, chemokine, and protective antigens for SARS-CoV 2 S proteins were predicted using appropriate tools. Results. B.1.617.1 variant S protein sequence was found to be highly stable and amphipathic. ABCpred and CTLpred analyses led to the identification of two potential antigenic B cell and T cell epitopes with starting amino acid positions at 60 and 82 (for B cell epitopes) and 54 and 98 (for T cell epitopes) having prediction scores > 0.8 . Further, RAMPAGE tool was used for determining the allowed and disallowed regions of the three-dimensional predicted structure of SARS-CoV-2 B.1.617.1 variant S protein. Conclusion. Together, the in silico analysis revealed the predicted structure of partial S protein, immunogenic properties, and possible regions for S protein of SARS-CoV-2 and provides a valuable prelude for engineering the targeted vaccine or drug against B.1.617.1 variant of SARS-CoV-2.