New Generation Of Vaccines Research Articles

Candidate vaccine construction against tick-born encephalitis based on hybrid recombinant flagG-protE-protein

The present work describes the construction of the gene encoding the recombinant protein flagG­protE, its synthesis, purification and study. The recombinant flagG­protE protein is a promising molecule for developing a candidate recombinant vaccine against tickborne encephalitis by the ability to bind to monoclonal antibodies (MCA) against native protein E of tick­borne encephalitis virus. The antigenic determinants of two recombinant proteins were studied: protE and flagG­protE using a panel of 8 MCA. The recombinant protein protE comprises the tick­borne encephalitis virus envelope protein and the flagGprotE recombinant protein has an additional flagG domain encoding flagellin G of Salmonella typhi. It was found that the MCA tested revealed epitopes on the recombinant protein protE. This indicates that the investigated recombinant protein has an antigenic structure similar to the antigenic structure of the native tick­borne encephalitis virus protein E. In the study of the recombinant protein flagG­protE by the ability to bind a panel of 8 MCA, only five of them react with epitopes of the tested protein. MCA 4F6, 7F10, and 6B9 did not recognize the corresponding epitope in the recombinant flagG­protE protein, while in the recombinant protein protE, these epitopes were detected successfully. Our data indicate that the antigenic structure of recombinant protE­protein can be changed under the influence of the flagellin domain, which in turn can lead to the unavailability of some antigenic determinants. This fact must be taken into account when constructing recombinant molecules with antigenic properties. Nevertheless, the fundamentally important regions in the region of the fusion peptide and III domain are antigenically present on the surface of the recombinant protein. This should ensure the formation of neutralizing antibodies, and the presence of a complete amino acid sequence of protein E in the recombinant protein induces the formation of a T­cell immune response. The emergence of a new generation of vaccines against tick­borne encephalitis with a higher level of safety and immunogenicity will improve the vaccine prevention of the population from tick­borne encephalitis.

Vaccine profile of PPV23: Beijing Minhai Biotech 23-valent pneumococcal vaccine

ABSTRACTIntroduction: Diseases caused by Streptococcus pneumoniae are a major public health problem worldwide, which can be effectively prevented by the 23-valent pneumococcal polysaccharide vaccines (PPV23).Areas covered: The Beijing Minhai PPV23 showed good safety and immunogenicity profiles in clinical trials. The immunogenicity of Beijing Minhai PPV23 was non-inferior to other licensed PPVs. Although PPV23 has been proved to be highly efficient and cost-effective, and was recommended for vaccination in high-risk populations in industrialized countries, the coverage of PPV23 vaccination was relatively low in developing countries.Expert commentary: The low vaccination proportions of PPV23 in China have not been improved in recent decades. Most of the populations with indications for receiving PPV23 were not aware of the possible benefits of PPV23. Moreover, PPV23 had some limitations, which called for the development of a new generation of vaccines against pneumococcal infection.

Sleeping Beauty and the Story of the Bacille Calmette-Guérin Vaccine.

ABSTRACTMycobacterium bovis BCG is the only available vaccine for protection against tuberculosis (TB). While BCG protects children from severe disease, it has little impact on pulmonary disease in adults. A recombinant BCG vaccine BCG ΔureC::hly (strain VPM1002) is in advanced clinical trials and shows promise for improved vaccine safety but little change in efficacy in animal models. A second-generation recombinant BCG vaccine with an additional deletion of the nuoG gene (BCG ΔureC::hly ΔnuoG) shows improved efficacy in a mouse model compared to that of VPM1002. BCG was first used in humans in 1921 and, like Sleeping Beauty pricked by the spinning wheel, we have slept for 100 years, showing a reluctance to invest in clinical development or in biomanufacturing capacity for TB vaccines. The advance of recombinant BCGs should awaken us from our sleep and call us to invest in new-generation TB vaccines and to protect the biomanufacture of our current BCG vaccine.

Potential of mannan or dextrin nanogels as vaccine carrier/adjuvant systems

Polymeric nanogels have been sophisticatedly designed promising a new generation of vaccine delivery/adjuvant systems capable of boosting immune response, a strategic priority in vaccine design. Here, nanogels made of mannan or dextrin were evaluated for their potential as carriers/adjuvants in vaccine formulations. Since lymph nodes are preferential target organs for vaccine delivery systems, nanogels were biotin-labeled, injected in the footpad of rats, and their presence in draining lymph nodes was assessed by immunofluorescence. Nanogels were detected in the popliteal and inguinal lymph nodes by 24 h upon subcutaneous administration, indicating entrapment in lymphatic organs. Moreover, the model antigen ovalbumin was physically encapsulated within nanogels and physicochemically characterized concerning size, zeta potential, ovalbumin loading, and entrapment efficiency. The immunogenicity of these formulations was assessed in mice intradermally immunized with ovalbumin–mannan or ovalbumin–dextrin by determining ovalbumin-specific antibody serum titers. Intradermal vaccination using ovalbumin–mannan elicited a humoral immune response in which ovalbumin-specific IgG1 levels were significantly higher than those obtained with ovalbumin alone, indicating a TH2-type response. In contrast, dextrin nanogel did not show adjuvant potential. Altogether, these results indicate that mannan nanogel is a material that should be explored as a future antigen delivery system.

The germinal center antibody response in health and disease.

The germinal center response is the delayed but sustained phase of the antibody response that is responsible for producing high-affinity antibodies of the IgG, IgA and/or IgE isotypes. B cells in the germinal center undergo re-iterative cycles of somatic hypermutation of immunoglobulin gene variable regions, clonal expansion, and Darwinian selection for cells expressing higher-affinity antibody variants. Alternatively, selected B cells can terminally differentiate into long-lived plasma cells or into a broad diversity of mutated memory B cells; the former secrete the improved antibodies to fight an infection and to provide continuing protection from re-infection, whereas the latter may jumpstart immune responses to subsequent infections with related but distinct infecting agents. Our understanding of the molecules involved in the germinal center reaction has been informed by studies of human immunodeficiency patients with selective defects in the production of antibodies. Recent studies have begun to reveal how innate immune recognition via Toll-like receptors can enhance the magnitude and selective properties of the germinal center, leading to more effective control of infection by a subset of viruses. Just as early insights into the nature of the germinal center found application in the development of the highly successful conjugate vaccines, more recent insights may find application in the current efforts to develop new generations of vaccines, including vaccines that can induce broadly protective neutralizing antibodies against influenza virus or HIV-1.

Estimated prevalence of smallpox vaccine contraindications in Israeli adolescents

BackgroundRoutine smallpox vaccination for military recruits was discontinued in Israel in 1996. However, Israeli guidelines recommend post-event mass-vaccination. This study aimed to estimate the rate of Israeli adolescents at risk of severe adverse events after vaccination during 1998−2013. MethodsThe study population included adolescents screened before military service in 1998−2013. Medical parameters correlating with contraindications to smallpox vaccination were retrieved from army databases, and were categorized by severity according to the Israeli post-event strategy. ResultsOf 1,180,964 individuals, 1.86% had vaccination contraindications in a post-event scenario. An additional 1.24% had contraindications in a pre-event scenario. There was an increase in the percentage of contraindications over time, attributed to the rising incidence of atopic-dermatitis. ConclusionsOnly a small percentage of the adolescent population is ineligible to receive the smallpox vaccine currently in use. This group may be protected by herd-immunity, or by new-generation vaccines designed to prevent severe adverse events.

Enhanced protective efficacy of a PRRSV DNA vaccine by absorption onto biodegradable PLGA/BPEI nanoparticle

Abstract Porcine reproductive and respiratory syndrome (PRRS) is one of economically devastating viral diseases of pigs, which has recently caused catastrophic losses in swine industry worldwide. Developing preventive measures to control PRRS outbreaks has been a challenge to the swine industry worldwide. Current PRRSV vaccination strategies provide only a limited protection. The safer and more effective new vaccines are urgently needed. Nanoparticles (NPs) as vaccine carriers have a broad application prospect in design of vaccine systems. PLGA nanoparticle-mediated delivery of vaccines has shown to be effective in eliciting protective immune response, administered by either mucosal or systemic routes. PEI, due to its high positive charge density, has been widely used as a cationic polymer for the preparation of the cationic PLGA particles. In this study, a synthetic ORF5 gene (SynORF5) of PRRSV as a model vaccine (pcDNA3.1-SynORF5), which has been employed and demonstrated that it could significantly induce the humoral and cellular immunity responses, was absorbed onto the PLGA/PEI nanoparticles. Moreover, we prepared PLGA nanoparticle-adsorbed PRRSV DNA vaccine and PEI-DNA complex, respectively. The results showed that all the experimental groups could significantly enhanced GP5-specific ELISA antibody, PRRSV-specific neutralizing antibody, IFN-γ level, as well as lymphocyte proliferation than the responses induced by pcDNA3.1-SynORF5. Among the experimental groups, PLGA-branched PEI nanoparticle induced the most efficient immune responses. The delivery systems and adjuvant in the research provide new path for the development of the new generation of vaccines against PRRSV.

Carbohydrate specific T cell stimulation by HIV envelope glycoprotein

Abstract HIV has been a major threat to human health and a protective AIDS vaccine has not as yet been developed. The design of the current generation of vaccines does not make use of specific scientific knowledge to maximize stimulation of critical immune cells (i.e., helper T cells) involved in producing protective antibodies. HIV-1 surface is decorated with a heavily glycosylated envelope protein called gp120, whose interaction with the CD4 molecule is the key step for the virus’s entry into CD4+ T cells. Gp120 glycans have been shown to play critical roles in Env structure, viral infectivity, antigenicity, receptor binding and HIV-1 transmission. Our goal is to identify CD4+ T cell repertoires recognizing the glycan shield of HIV-1 envelope glycoprotein, gp120. We have gained significant evidence for glycan/glycopeptide presentation on the antigen presenting cell (APC) surfaces serving as potential epitopes to induce carbohydrate-specific T cells (Tcarb) response. Additionally, we demonstrate that certain populations of CD4+ T cells differentiate between glycosylated and non-glycosylated gp120 epitopes, suggesting carbohydrate recognition by CD4+ T cells. Using the discovery of such Tcarbs and their glycan epitopes, we can design and develop knowledge-based, new-generation HIV vaccines that will elicit strong and long lasting immune response to protect from HIV. We believe our study will yield a new platform to develop a new-generation of protective HIV vaccines.

Development of a Luminex-Based DIVA Assay for Serological Detection of African Horse Sickness Virus in Horses.

African horse sickness (AHS) is considered a fatal re-emergent vector-borne disease of horses. In the absence of any effective treatment for AHS, vaccination remains the most effective form of disease control. The new generation of vaccines, such as one based on purified, inactivated AHS virus (AHSV, serotype 4), which does not induce antibodies against non-structural protein 3 (NS3), enables the development of diagnostic methods that differentiate infected from vaccinated animals (DIVA assays). As detecting AHS in AHSV-free countries may lead to restrictions on international animal movements and thereby cause significant economic damage, these DIVA assays are crucial for reducing movement restrictions. In this article, we describe a Luminex-based multiplex assay for DIVA diagnosis of AHS, and we validate it in a duplex format to detect antibodies against structural protein 7 (VP7) and NS3 in serum samples from horses vaccinated with inactivated AHSV4 vaccine or infected with a live virus of the same serotype. Results of the Luminex-based assay for detecting anti-NS3 antibodies showed good positive correlation with results from an in-house enzyme-linked immunosorbent assay (ELISA). Thus, the Luminex-based technique described here may allow multiplex DIVA antibody detection in a single sample in less than 2h, and it may prove adaptable for the development of robust, multiplex serological assays.

Pertussis: Microbiology, Disease, Treatment, and Prevention.

Pertussis is a severe respiratory infection caused by Bordetella pertussis, and in 2008, pertussis was associated with an estimated 16 million cases and 195,000 deaths globally. Sizeable outbreaks of pertussis have been reported over the past 5 years, and disease reemergence has been the focus of international attention to develop a deeper understanding of pathogen virulence and genetic evolution of B. pertussis strains. During the past 20 years, the scientific community has recognized pertussis among adults as well as infants and children. Increased recognition that older children and adolescents are at risk for disease and may transmit B. pertussis to younger siblings has underscored the need to better understand the role of innate, humoral, and cell-mediated immunity, including the role of waning immunity. Although recognition of adult pertussis has increased in tandem with a better understanding of B. pertussis pathogenesis, pertussis in neonates and adults can manifest with atypical clinical presentations. Such disease patterns make pertussis recognition difficult and lead to delays in treatment. Ongoing research using newer tools for molecular analysis holds promise for improved understanding of pertussis epidemiology, bacterial pathogenesis, bioinformatics, and immunology. Together, these advances provide a foundation for the development of new-generation diagnostics, therapeutics, and vaccines.

Design of the ATAQ peptide and its evaluation as an immunogen to develop a Rhipicephalus vaccine

Tick infestation may cause several problems including affecting domestic animal health and reducing the production of meat and milk, among others. Resistance to several classes of acaricides have been reported, forcing researchers to search for alternative measures, such as vaccines against ticks, to ensure tick control while having no or at least low negative impacts on the environment and public health. However, the current commercially available vaccines in different strains of Rhipicephalus microplus are reported to be of low efficacy. Fortunately, reverse vaccinology approaches have shown positive results in the new generation of vaccines. On this basis, a synthetic peptide from the ATAQ protein, which is present in the gut and Malpighi tubes of R. microplus, was synthesized. The ATAQ proteins were isolated, characterized and sequenced from several species of the genus Rhipicephalus. The alignment showed 93.3% identity among DNA sequences of ATAQs from these species. Because of this, immunization trials with this peptide were conducted on mice, rabbits and cattle to evaluate the humoral immune response and the efficacy against Rhipicephalus sanguineus in addition to R. microplus. Based on recent results, we conclude that reverse vaccinology is a promising approach because it is more accurate and faster than conventional methods in the detection of potential antigens to use in anti-tick vaccines. It is not only applicable against R. microplus but also against tick species that play important roles in spreading other diseases. ATAQ proteins should be considered as the antigen in new trials to develop a multi-antigenic vaccine. Although these peptides behave as hapten and are not able to be recognized by the immune system on its own, using carriers and adjuvants helps its presentation and induces strong immune responses. Furthermore, an efficiency of 35% reduction in overall life cycle parameters was reported for R. microplus (98% for ELISA responder animals) and 47% for R. sanguineus. Although not yet enough to prevent the environment to infestation of ticks, this still constitutes a promising strategy that could be applied to integrated measures on tick control and in new research that develops anti-tick vaccines.

Mechanistic Analysis of the Effect of Deamidation on the Immunogenicity of Anthrax Protective Antigen.

The spontaneous modification of proteins, such as deamidation of asparagine residues, can significantly affect the immunogenicity of protein-based vaccines. Using a "genetically deamidated" form of recombinant protective antigen (rPA), we have previously shown that deamidation can decrease the immunogenicity of rPA, the primary component of new-generation anthrax vaccines. In this study, we investigated the biochemical and immunological mechanisms by which deamidation of rPA might decrease the immunogenicity of the protein. We found that loss of the immunogenicity of rPA vaccine was independent of the presence of adjuvant. We assessed the effect of deamidation on the immunodominant neutralizing B-cell epitopes of rPA and found that these epitopes were not significantly affected by deamidation. In order to assess the effect of deamidation on T-cell help for antibody production elicited by rPA vaccine, we examined the ability of the wild-type and genetically deamidated forms of rPA to serve as hapten carriers. We found that when wild-type and genetically deamidated rPA were modified to similar extents with 2,4-dinitrophenyl hapten (DNP) and then used to immunize mice, higher levels of anti-DNP antibodies were elicited by wild-type DNP-rPA than those elicited by the genetically deamidated DNP-rPA, indicating that wild-type rPA elicits more T-cell help than the genetically deamidated form of the protein. These results suggest that a decrease in the ability of deamidated rPA to elicit T-cell help for antibody production is a possible contributor to its lower immunogenicity.

The induction of antigen-specific CTL by in situ Ad-REIC gene therapy.

An adenovirus vector carrying the human Reduced Expression in Immortalized Cell (REIC)/Dkk-3 gene (Ad-REIC) mediates simultaneous induction of cancer-selective apoptosis and augmentation of anticancer immunity. In our preclinical and clinical studies, in situ Ad-REIC gene therapy showed remarkable direct and indirect antitumor effects to realize therapeutic cancer vaccines. We herein aimed to confirm the induction of tumor-associated antigen-specific cytotoxic T lymphocytes (CTLs) by Ad-REIC. Using an ovalbumin (OVA), a tumor-associated antigen, expressing E.G7 tumor-bearing mouse model, we investigated the induction and expansion of OVA-specific CTLs responsible for indirect, systemic effects of Ad-REIC. The intratumoral administration of Ad-REIC mediated clear antitumor effects with the accumulation of OVA-specific CTLs in the tumor tissues and spleen. The CD86-positive dendritic cells (DCs) were upregulated in the tumor draining lymph nodes of Ad-REIC-treated mice. In a dual tumor-bearing mouse model in the left and right back, Ad-REIC injection in one side significantly suppressed the tumor growth on both sides and significant infiltration of OVA-specific CTLs into non-injected tumor was also detected. Consequently, in situ Ad-REIC gene therapy is expected to realize a new-generation cancer vaccine via anticancer immune activation with DC and tumor antigen-specific CTL expansion.

The role of ISCOMATRIX bilayer composition to induce a cell mediated immunity and protection against leishmaniasis in BALB/c mice.

Development of new generation of vaccines against leishmaniasis is possible because long-term protection is usually seen after recovery from cutaneous leishmaniasis. ISCOMATRIX is particulate antigen delivery system composed of antigen, cholesterol, phospholipid and saponin. In this study, the role of ISCOMATRIX bilayer composition made by different phase transition temperature (Tc) to induce a type of immune response and protection against leishmaniasis was assessed. ISCOMATRIX formulations with different bilayer compositions consisting of EPC (Tc <0 °C), DMPC (Tc 23 °C) and DSPC (Tc 54 °C) were prepared. Different ISCOMATRIX formulations were mixed with soluble Leishmania antigens (SLA). BALB/c mice were immunized subcutaneously, three times with 2-week intervals. As criteria for protection, footpads swelling, parasite burden, determination of IgG isotypes and the level of IFN-γ and IL-4 were assessed. Although the groups of mice immunized with ISCOMATRIX DMPC or ISCOMATRIX DSPC showed the smallest footpad swelling and least parasite burden compared with the buffer group, the difference was not significant. Moreover, the highest level of IFN- γ and IL-4 was observed in the splenocytes of mice immunized with ISCOMATRIX DMPC or ISCOMATRIX DSPC, respectively. After challenge, the mice immunized with ISCOMATRIX DSPC showed the highest elevation of IgG, IgG1 and IgG2a antibodies (P<0.01) compared with control group. However, our results indicated that ISCOMATRIX EPC, DMPC or DSPC generated a mixed Th1/Th2 response that was not protective. Our results showed that the adjuvanticity of prepared ISCOMATRIX doesn't influence with different phospholipids at least in our mice model.

Efficient and Durable Vaccine against Intimin β of Diarrheagenic E. Coli Induced by Clay Nanoparticles.

Improved strategies are urgently required to control infections with enterohemorrhagic Escherichia coli and enteropathogenic E. coli, two dominant zoonotic enteric pathogens responsible for a wide spectrum of illnesses as well as deaths of human being, with tremendous financial cost worldwide. The present study investigates the capacity of two clay nanoparticles (NPs) with opposite surface charges, namely synthetic layered double hydroxide (LDH) and hectorite (HEC) NPs as adjuvants to promote strong immune responses against the infections. Here both LDH and HEC NPs are showed to be able to carry an appreciable amount of Intimin β (1.1 and 4.4 mg per mg clay nanomaterials, respectively) and significantly facilitate antigen uptake by antigen-presenting cells. Remarkably, these clay NPs induce strong antibody and cell-mediated immune responses, which are much higher than that by the potent adjuvant, QuilA. Furthermore, these strong immune responses are well maintained for at least four months in the mouse model, during which there are no changes in histopathology of the animal organs. Collectively these data demonstrate the suitability of LDH and HEC NPs as useful adjuvants in new-generation vaccine formulations to control various infectious diseases.

СУЧАСНІ ТЕНДЕНЦІЇ ВПРОВАДЖЕННЯ ВАКЦИНАЦІЇ ПРОТИ ГРИПУ

&lt;p&gt;&lt;em&gt;Для вакцинопрофілактики грипу необхідно застосування вакцин нового покоління – етіологічно актуальних, як засобу індивідуального захисту та захисту груп медичного та епідемічного ризику. &lt;/em&gt;&lt;em&gt;&lt;/em&gt;&lt;/p&gt;&lt;strong&gt;&lt;em&gt;Ключові слова:&lt;/em&gt;&lt;/strong&gt;&lt;em&gt; грип, вакцинація.&lt;/em&gt;

Reverse Vaccinology: The Pathway from Genomes and Epitope Predictions to Tailored Recombinant Vaccines.

In this chapter, we review the computational approaches that have led to a new generation of vaccines in recent years. There are many alternative routes to develop vaccines based on the technology of reverse vaccinology. We focus here on bacterial infectious diseases, describing the general workflow from bioinformatic predictions of antigens and epitopes down to examples where such predictions have been used successfully for vaccine development.

DNA Vaccination in Chickens.

Robust and sustainable development of poultry industry requires prevention of deadly infectious diseases. Vigorous vaccination of the birds is a routine practice; however, the live and inactivated vaccines that are used have inherent disadvantages. New-generation vaccines such as DNA vaccines offer several advantages over conventional vaccines. DNA vaccines, which encode an antigen of interest or multiple antigens in the target host, are stable, easy to produce and administer, do not require cold chain maintenance, and are not affected by the maternal antibodies. In addition, DNA vaccines can also be administered in ovo, and thus, mass vaccination and early induction of immune response can effectively be achieved. In this chapter, we focus on the development of DNA vaccines against important infectious viral as well as parasitic diseases of poultry.

Optimized production of HIV-1 virus-like particles by transient transfection in CAP-T cells.

HIV-1 virus-like particles (VLPs) have great potential as new-generation vaccines. The novel CAP-T cell line is used for the first time to produce Gag-GFP HIV-1 VLPs by means of polyethylenimine (PEI)-mediated transient transfection. CAP-T cells are adapted to grow to high cell densities in serum-free medium, and are able to express complex recombinant proteins with human post-translational modifications. Furthermore, this cell line is easily transfected with PEI, which offers the flexibility to rapidly generate and screen a number of candidates in preclinical studies. Transient transfection optimization of CAP-T cells has been performed systematically in this work. It is determined that for optimal production, cells need to be growing at mid-exponential phase, Protein Expression Medium (PEM) medium has to be added post-transfection, and cells can be transfected by independent addition of DNA and PEI with no prior complexation. A Box-Behnkenexperimental design is used to optimize cell density at time of transfection, DNA/cell and PEI/cell ratios. The optimal conditions determined are transfection at a density of 3.3E+06 cells/mL with 0.5pg of DNA/cell and 3pg of PEI/cell. Using the optimized protocol, 6×10(10) VLP/mL are obtained, demonstrating that CAP-T is a highly efficient cell line for the production of HIV-1 VLPs and potentially other complex viral-based biotherapeutics.

Protecting Newborns Against Pertussis: Treatment and Prevention Strategies.

Pertussis is a potentially severe respiratory disease, which affects all age groups from young infants to older adults and is responsible for an estimated 195,000 deaths occurred globally in 2008. Active research is ongoing to better understand the pathogenesis, immunology, and diagnosis of pertussis. For diagnosis, molecular assays (e.g., polymerase chain reaction) for detection of Bordetella pertussis have become more widely available and support improved outbreak detection. In children, pertussis vaccines have been incorporated into routine immunization schedules and deployed for pertussis outbreak control. Lower levels of vaccine coverage are now being observed in communities where vaccine hesitancy is rising. Additionally, recognition that newborn babies are at risk of pertussis in the USA and UK has led to recommendations to immunize pregnant women. Among adolescents and older adults in the USA, Tetanus Toxoid, Reduced Diphtheria Toxoid and Acellular pertussis (Tdap) Vaccines are recommended, but substantial individual- and system-level barriers exist that will make achieving national Healthy People 2020 targets for immunization challenging. Current antimicrobial regimens for pertussis are focused on reducing the severity of disease, reducing rates of sequelae, and minimizing transmission of infection to susceptible individuals. Continued surveillance for pertussis will be important to identify opportunities for reducing young infants' exposure and reducing the impact of outbreaks among school-aged children. Laboratory-based surveillance for newly emerging strains of B. pertussis will be important to identify strains that may evade protection elicited by currently available vaccines. Efforts to develop new-generation pertussis vaccines should be considered now in anticipation of vaccine development programs, which may require ten or more years to deliver a licensed vaccine.