DNA vaccines against influenza viruses

SARS-CoV-2 Vaccines: Types, Working Principle, and Its Impact on Thrombosis and Gastrointestinal Disorders

In the current scenario of the coronavirus pandemic caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), considerable efforts have been made to control the pandemic by the development of a strong immune system through massive vaccination. Just after the discovery of the genetic sequences of SARS-CoV-2, the development of vaccines became the prime focus of scientists around the globe. About 200 SARS-CoV-2 candidate vaccines have already been entered into preclinical and clinical trials. Various traditional and novel approaches are being utilized as a broad range of platforms. Viral vector (replicating and non-replicating), nucleic acid (DNA and RNA), recombinant protein, virus-like particle, peptide, live attenuated virus, an inactivated virus approaches are the prominent attributes of the vaccine development. This review article includes the current knowledge about the platforms used for the development of different vaccines, their working principles, their efficacy, and the impacts of COVID-19 vaccines on thrombosis. We provide a detailed description of the vaccines that are already approved by administrative authorities. Moreover, various strategies utilized in the development of emerging vaccines that are in the trial phases along with their mode of delivery have been discussed along with their effect on thrombosis and gastrointestinal disorders.

Viral vector and nucleic acid vaccines against COVID-19: A narrative review

After about 2 years since the first detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in Wuhan, China, in December 2019 that resulted in a worldwide pandemic, 6.2 million deaths have been recorded. As a result, there is an urgent need for the development of a safe and effective vaccine for coronavirus disease 2019 (COVID-19). Endeavors for the production of effective vaccines inexhaustibly are continuing. At present according to the World Health Organization (WHO) COVID-19 vaccine tracker and landscape, 153 vaccine candidates are developing in the clinical phase all over the world. Some new and exciting platforms are nucleic acid-based vaccines such as Pfizer Biontech and Moderna vaccines consisting of a messenger RNA (mRNA) encoding a viral spike protein in host cells. Another novel vaccine platform is viral vector vaccine candidates that could be replicating or nonreplicating. These types of vaccines that have a harmless viral vector like adenovirus contain a genome encoding the spike protein of SARS-CoV-2, which induces significant immune responses. This technology of vaccine manufacturing has previously been used in many human clinical trials conducted for adenoviral vector-based vaccines against different infectious agents, including Ebola virus, Zika virus, HIV, and malaria. In this paper, we have a review of nucleic acid-based vaccines that are passing their phase 3 and 4 clinical trials and discuss their efficiency and adverse effects.

Hemagglutinin-based DNA vaccines containing trimeric self-assembling nanoparticles confer protection against influenza

Influenza viruses continue to threaten public health, and currently available vaccines provide insufficient immunity against seasonal and pandemic influenza. The use of recombinant trimeric hemagglutinin (HA) as an Ag provides an attractive alternative to current influenza vaccines. Aiming to develop an effective vaccine with rapid production, robust immunogenicity, and high protective efficiency, a DNA vaccine was designed by fusing influenza virus HA with self-assembled ferritin nanoparticles, denoted as HA-F. This candidate vaccine was prepared and purified in a 293-6E cell eukaryotic expression system. After BALB/c mice were immunized with 100 μg of HA-F DNA 3 times, HA-F elicited significant HA-specific humoral immunity and T cell immune responses. The HA-F DNA vaccine also conferred protection in mice against a lethal infection of homologous A/17/California/2009/38 (H1N1) virus. These results suggest that the HA-F DNA vaccine is a competitive vaccine candidate and presents a promising vaccination approach against influenza viruses.

SARS-CoV-2 (Covid-19) vaccines structure, mechanisms and effectiveness: A review

The world has been suffering from COVID-19 disease for more than a year, and it still has a high mortality rate. In addition to the need to minimize transmission of the virus through non-pharmacological measures such as the use of masks and social distance, many efforts are being made to develop a variety of vaccines to prevent the disease worldwide. So far, several vaccines have reached the final stages of safety and efficacy in various phases of clinical trials, and some, such as Moderna/NIAID and BioNTech/Pfizer, have reported very high safety and protection. The important point is that comparing different vaccines is not easy because there is no set standard for measuring neutralization. In this study, we have reviewed the common platforms of COVID-19 vaccines and tried to present the latest reports on the effectiveness of these vaccines.

The Human Antibody Response to the Influenza Virus Neuraminidase Following Infection or Vaccination

The influenza virus neuraminidase (NA) is primarily involved in the release of progeny viruses from infected cells—a critical role for virus replication. Compared to the immuno-dominant hemagglutinin, there are fewer NA subtypes, and NA experiences a slower rate of antigenic drift and reduced immune selection pressure. Furthermore, NA inhibiting antibodies prevent viral egress, thus preventing viral spread. Anti-NA immunity can lessen disease severity, reduce viral shedding, and decrease viral lung titers in humans and various animal models. As a result, there has been a concerted effort to investigate the possibilities of incorporating immunogenic forms of NA as a vaccine antigen in future vaccine formulations. In this review, we discuss NA-based immunity and describe several human NA-specific monoclonal antibodies (mAbs) that have a broad range of protection. We also review vaccine platforms that are investigating NA antigens in pre-clinical models and their potential use for next-generation influenza virus vaccines. The evidence presented here supports the inclusion of immunogenic NA in future influenza virus vaccines.

Next-generation COVID-19 vaccines: Opportunities for vaccine development and challenges in tackling COVID-19

The ongoing COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a global threat. Although non-pharmaceutical interventions have been rigorously and widely implemented, living conditions caused by the pandemic will last until highly effective vaccines are successfully improved and globally administered. Several first-generation COVID-19 vaccines were approved at the end of 2020. However, the COVID-19 pandemic is persisting worldwide. To be clear, the efficiency and the coverage of current vaccines are insufficient, but newly emerging and rapidly spreading variants are the most pressing concern. A second-generation COVID-19 vaccine worth mentioning, NVX-CoV2373, has demonstrated 90% overall efficacy as well as a high level of efficacy against circulating variants in Phase 3 clinical trials. Currently, NVX-CoV2373 is the only vaccine that has proven successful against variants during Phase 3/4 trials. Therefore, developing the next generation of vaccines is a promising strategy to ultimately prevail against SARS-CoV-2. This review provides up-to-date information on COVID-19 vaccines in terms of their efficacy and new platforms and the progression of COVID-19 vaccination. Moreover, this review also summarizes the efficacy of approved COVID-19 vaccines against variants. Lastly, this review highlights the global challenges for COVID-19 vaccines in development and vaccination, and it discusses opportunities for development of future COVID-19 vaccines and vaccination coverage.

A conserved multi-epitope-based vaccine designed by targeting hemagglutinin protein of highly pathogenic avian H5 influenza viruses

The highly pathogenic avian H5N1 influenza viruses have been recognized as a potential pandemic threat to humans, and to the poultry industry since 1997. H5 viruses consist of a high mutation rate, so universal vaccine designing is very challenging. Here, we describe a vaccinomics approach to design a novel multi-epitope influenza vaccine, based on the highly conserved regions of surface glycoprotein, Hemagglutinin (HA). Initially, the HA protein sequences from Bangladeshi origin were retrieved and aligned by ClustalW. The sequences of 100% conserved regions extracted and analyzed to select the highest potential T-cell and B-cell epitope. The HTL and CTL analyses using IEDB tools showed that DVWTYNAELLVLMEN possesses the highest affinity with MHC class I and II alleles, and it has the highest population coverage. The docking simulation study suggests that this epitope has the potential to interact with both MHC class I and MHC class II. The B-cell epitope prediction provides a potential peptide, GAIAGFIEGGWQGM. We further retrieved HA sequences of 3950 avian and 250 human H5 isolates from several populations of the world, where H5 was an epidemic. Surprisingly, these epitopes are more than 98% conserved in those regions which indicate their potentiality as a conserved vaccine. We have proposed a multi-epitope vaccine using these sequences and assess its stability and potentiality to induce B-cell immunity. In vivo study is necessary to corroborate this epitope as a vaccine, however, setting forth groundwork for wet-lab studies essential to mitigate pandemic threats and provide cross-protection of both avian and humans against H5 influenza viruses.

COVID-19 vaccine: A recent update in pipeline vaccines, their design and development strategies

Coronavirus Disease 2019 named as COVID-19 imposing a huge burden on public health as well as global economies, is caused by a new strain of betacoronavirus named as SARS-CoV-2. The high transmission rate of the virus has resulted in current havoc which highlights the need for a fast and effective approach either to prevent or treat the deadly infection. Development of vaccines can be the most prominent approach to prevent the virus to cause COVID-19 and hence will play a vital role in controlling the spread of the virus and reducing mortality. The virus uses its spike proteins for entering into the host by interacting with a specific receptor called angiotensin converting enzyme-2 (ACE2) present on the surface of alveolar cells in the lungs. Researchers all over the world are targeting the spike protein for the development of potential vaccines. Here, we discuss the immunopathological basis of vaccine designing that can be approached for vaccine development against SARS-CoV-2 infection and different platforms that are being used for vaccine development. We believe this review will increase our understanding of the vaccine designing against SARS-CoV-2 and subsequently contribute to the control of SARS-CoV-2 infections. Also, it gives an insight into the current status of vaccine development and associated outcomes reported at different phases of trial.

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Either the S protein of the SARS-CoV-2 or the whole pathogen is targeted at the development of vaccines against COVID-19.

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Lymphocytopenia and Cytokine storm are two major manifestations associated with innate immune response generated against COVID-19.

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There are 44 vaccine candidates in clinical phase and 154 in preclinical phase of vaccine development.

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The major hurdle in establishing vaccine's efficacy being its effectiveness and safety at each step among diverse population.

New Technologies for Influenza Vaccines

Vaccine development has been hampered by the long lead times and the high cost required to reach the market. The 2020 pandemic, caused by a new coronavirus (SARS-CoV-2) that was first reported in late 2019, has seen unprecedented rapid activity to generate a vaccine, which belies the traditional vaccine development cycle. Critically, much of this progress has been leveraged off existing technologies, many of which had their beginnings in influenza vaccine development. This commentary outlines the most promising of the next generation of non-egg-based influenza vaccines including new manufacturing platforms, structure-based antigen design/computational biology, protein-based vaccines including recombinant technologies, nanoparticles, gene- and vector-based technologies, as well as an update on activities around a universal influenza vaccine.

Considerations for setting occupational exposure limits for novel pharmaceutical modalities

In order to develop new and effective medicines, pharmaceutical companies must be modality agnostic. As science reveals an enhanced understanding of biological processes, new therapeutic modalities are becoming important in developing breakthrough therapies to treat both rare and common diseases. As these new modalities progress, concern and uncertainty arise regarding their safe handling by the researchers developing them, employees manufacturing them and nurses administering them. This manuscript reviews the available literature for emerging modalities (including oligonucleotides, monoclonal antibodies, fusion proteins and bispecific antibodies, antibody-drug conjugates, peptides, vaccines, genetically modified organisms, and several others) and provides considerations for occupational health and safety-oriented hazard identification and risk assessments to enable timely, consistent and well-informed hazard identification, hazard communication and risk-management decisions. This manuscript also points out instances where historical exposure control banding systems may not be applicable (e.g. oncolytic viruses, biologics) and where other occupational exposure limit systems are more applicable (e.g. Biosafety Levels, Biologic Control Categories).

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Review of toxicology and pharmacology information for novel therapeutic modalities.

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Identification of occupational hazards associated with novel therapeutic modalities.

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Occupational hazards and exposure risks differ across pharmaceutical modalities.

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Occupational exposure control banding systems are not one size fits all.

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Banding system variations offer benefits while enabling proper exposure controls.

Interleukin 12-containing influenza virus-like-particle vaccine elevate its protective activity against heterotypic influenza virus infection

To produce monovalent and bivalent influenza vaccines composed of virus-like particles (VLPs) containing hemagglutinin (HA), we generated four recombinant Baculoviruses derived from Bombyx mori nuclear polyhedrosis virus (BmNPV) and Autographa california nuclear polyhedrosis virus (AcNPV). Monovalent Fukushima (A/tufted duck/Fukushima/16/2011 [H5N1]) (FkH5) and Anhui (A/Anhui/1/2013 [H7N9]) (AnH7) VLP influenza vaccines were produced in silkworm pupae infected with FkH5-BmNPV or AnH7-BmNPV. To produce a bivalent FkH5 and AnH7 vaccine, the pupae were simultaneously inoculated with FkH5-BmNPV and AnH7-BmNPV. Then, interleukin (IL)-containing bivalent vaccines were produced by Eri silkworm pupae following triple infection with FkH5-AcNPV, AnH7-AcNPV, and IL-12-AcNPV. Fluorescent antibody tests in Sf9 cells triple-infected with FkH5-AcNPV, AnH7-AcNPV, and IL-12-AcNPV showed coexpression of FkH5, AnH7, and IL-12 antigens, suggesting the presence of VLPs containing all three antigens. We then performed competitive hemagglutination inhibition (CHI) tests to calculate the VLP vaccine constituents. Inoculation with two recombinant viruses led to the production of bivalent vaccines containing very similar amounts of the H5 and H7 antigens, suggesting that our dual infection system can be used to produce bivalent VLP vaccines. Immunisation of mice with our developed monovalent and bivalent VLP vaccines induced the production of HI antibody, which protected against a sublethal dose of influenza virus. These IL-12-containing vaccines tended to display increased protection against hetero-subtype influenza viruses.

Functional growth inhibition of influenza A and B viruses by liquid and powder components of leaves from the subtropical plant Melia azedarach L

We evaluated the anti-influenza-virus effects of Melia components and discuss the utility of these components. The effects of leaf components of Melia azedarach L. on viruses were examined, and plaque inhibition tests were performed. The in vivo efficacy of M. azedarach L. was tested in a mouse model. Leaf components of Melia azedarach L. markedly inhibited the growth of various influenza viruses. In an initial screening, multiplication and haemagglutination (HA) activities of H1N1, H3N2, H5, and B influenza viruses were inactivated by the liquid extract of leaves of M. azedarach L. (MLE). Furthermore, plaque inhibition titres of H1N1, H3N2, and B influenza viruses treated with MLE ranged from 103.7 to 104.2. MLE possessed high plaque-inhibitory activity against pandemic avian H5N1, H7N9, and H9N2 vaccine candidate strains, with a plaque inhibition titre of more than 104.2. Notably, the buoyant density decreased from 1.175 to 1.137 g/cm3, and spikeless particles appeared. We identified four anti-influenza virus substances: pheophorbide b, pheophorbide a, pyropheophorbide a, and pheophytin a. Photomorphogenesis inside the envelope may lead to removal of HA and neuraminidase spikes from viruses. Thus, MLE could efficiently remove floating influenza virus in the air space without toxicity. Consistent with this finding, intranasal administration of MLE in mice significantly decreased the occurrence of pneumonia. Additionally, leaf powder of Melia (MLP) inactivated influenza viruses and viruses in the intestines of chickens. MLE and MLP may have applications as novel, safe biological disinfectants for use in humans and poultry.

Novel Platforms for the Development of a Universal Influenza Vaccine

Despite advancements in immunotherapeutic approaches, influenza continues to cause severe illness, particularly among immunocompromised individuals, young children, and elderly adults. Vaccination is the most effective way to reduce rates of morbidity and mortality caused by influenza viruses. Frequent genetic shift and drift among influenza-virus strains with the resultant disparity between circulating and vaccine virus strains limits the effectiveness of the available conventional influenza vaccines. One approach to overcome this limitation is to develop a universal influenza vaccine that could provide protection against all subtypes of influenza viruses. Moreover, the development of a novel or improved universal influenza vaccines may be greatly facilitated by new technologies including virus-like particles, T-cell-inducing peptides and recombinant proteins, synthetic viruses, broadly neutralizing antibodies, and nucleic acid-based vaccines. This review discusses recent scientific advances in the development of next-generation universal influenza vaccines.

Comparison of the Protective Efficacy of Neutralizing Epitopes of 2009 Pandemic H1N1 Influenza Hemagglutinin

The 2009 H1N1 influenza (Pdm09) pandemic has been referred to as the first influenza pandemic of the twenty-first century. There is a marked difference in antigenicity between the pandemic H1N1 virus and past seasonal H1N1 viruses, which allowed the pandemic virus to spread rapidly in humans. Antibodies (Abs) against hemagglutinin (HA), especially neutralizing Abs against epitopes in the head of HA, play critical roles in defending the host against the virus. Some preexisting neutralizing Abs that recognize neutralizing epitopes of Pdm09 HA, thereby affording cross-protection, have been reported. To better understand the protective effects of epitopes in Pdm09 HA, we constructed a series of plasmid DNAs (DNA vaccines) by cloning various combinations of Pdm09 neutralizing epitopes into the HA backbone derived from A/PR/8/1934 (H1N1). We subsequently compared the protective immune responses induced by these various forms of HA in a mouse model. We found that the plasmid DNAs with epitope substitutions provided better protection against lethal virus challenge and induced higher strain-specific antibody titers, with epitope Sa being the most effective. Moreover, the combination of epitopes Sa and Sb provided almost complete protection in mice. These findings provide new insights into the protective efficacy of neutralizing epitopes of influenza HA.

Refining the approach to vaccines against influenza A viruses with pandemic potential

Vaccination is the most effective strategy for prevention and control of influenza. Timely production and deployment of seasonal influenza vaccines is based on an understanding of the epidemiology of influenza and on global disease and virologic surveillance. Experience with seasonal influenza vaccines guided the initial development of pandemic influenza vaccines. A large investment in pandemic influenza vaccines in the last decade has resulted in much progress and a body of information that can now be applied to refine the established paradigm. Critical and complementary considerations for pandemic influenza vaccines include improved assessment of the pandemic potential of animal influenza viruses, proactive development and deployment of pandemic influenza vaccines, and application of novel platforms and strategies for vaccine production and administration.

Developing Universal Influenza Vaccines: Hitting the Nail, Not Just on the Head

Influenza viruses have a huge impact on public health. Current influenza vaccines need to be updated annually and protect poorly against antigenic drift variants or novel emerging subtypes. Vaccination against influenza can be improved in two important ways, either by inducing more broadly protective immune responses or by decreasing the time of vaccine production, which is relevant especially during a pandemic outbreak. In this review, we outline the current efforts to develop so-called “universal influenza vaccines”, describing antigens that may induce broadly protective immunity and novel vaccine production platforms that facilitate timely availability of vaccines.

Current advancements and potential strategies in the development of MERS-CoV vaccines

Middle East respiratory syndrome (MERS) is a newly emerging infectious disease caused by a novel coronavirus, MERS-coronavirus (MERS-CoV), a new member in the lineage C of β-coronavirus (β-CoV). The increased human cases and high mortality rate of MERS-CoV infection make it essential to develop safe and effective vaccines. In this review, the current advancements and potential strategies in the development of MERS vaccines, particularly subunit vaccines based on MERS-CoV spike (S) protein and its receptor-binding domain (RBD), are discussed. How to improve the efficacy of subunit vaccines through novel adjuvant formulations and routes of administration as well as currently available animal models for evaluating the in vivo efficacy of MERS-CoV vaccines are also addressed. Overall, these strategies may have important implications for the development of effective and safe vaccines for MERS-CoV in the future.

H5N1 vaccines in humans

The spread of highly pathogenic avian H5N1 influenza viruses since 1997 and their virulence for poultry and humans has raised concerns about their potential to cause an influenza pandemic. Vaccines offer the most viable means to combat a pandemic threat. However, it will be a challenge to produce, distribute and implement a new vaccine if a pandemic spreads rapidly. Therefore, efforts are being undertaken to develop pandemic vaccines that use less antigen and induce cross-protective and long-lasting responses, that can be administered as soon as a pandemic is declared or possibly even before, in order to prime the population and allow for a rapid and protective antibody response. In the last few years, several vaccine manufacturers have developed candidate pandemic and pre-pandemic vaccines, based on reverse genetics and have improved the immunogenicity by formulating these vaccines with different adjuvants. Some of the important and consistent observations from clinical studies with H5N1 vaccines are as follows: two doses of inactivated vaccine are generally necessary to elicit the level of immunity required to meet licensure criteria, less antigen can be used if an oil-in-water adjuvant is included, in general antibody titers decline rapidly but can be boosted with additional doses of vaccine and if high titers of antibody are elicited, cross-reactivity against other clades is observed. Prime-boost strategies elicit a more robust immune response. In this review, we discuss data from clinical trials with a variety of H5N1 influenza vaccines. We also describe studies conducted in animal models to explore the possibility of reassortment between pandemic live attenuated vaccine candidates and seasonal influenza viruses, since this is an important consideration for the use of live vaccines in a pandemic setting.

Experimental vaccines against potentially pandemic and highly pathogenic avian influenza viruses

Influenza A viruses continue to emerge and re-emerge, causing outbreaks, epidemics and occasionally pandemics. While the influenza vaccines licensed for public use are generally effective against seasonal influenza, issues arise with production, immunogenicity, and efficacy in the case of vaccines against pandemic and emerging influenza viruses, and highly pathogenic avian influenza virus in particular. Thus, there is need of improved influenza vaccines and vaccination strategies. This review discusses advances in alternative influenza vaccines, touching briefly on licensed vaccines and vaccine antigens; then reviewing recombinant subunit vaccines, virus-like particle vaccines and DNA vaccines, with the main focus on virus-vectored vaccine approaches.

New strategies for the development of H5N1 subtype influenza vaccines: progress and challenges

The emergence and spread of highly pathogenic avian influenza (H5N1) viruses among poultry in Asia, the Middle East, and Africa have fueled concerns of a possible human pandemic, and spurred efforts towards developing vaccines against H5N1 influenza viruses, as well as improving vaccine production methods. In recent years, promising experimental reverse genetics-derived H5N1 live attenuated vaccines have been generated and characterized, including vaccines that are attenuated through temperature-sensitive mutation, modulation of the interferon antagonist protein, or disruption of the M2 protein. Live attenuated influenza virus vaccines based on each of these modalities have conferred protection against homologous and heterologous challenge in animal models of influenza virus infection. Alternative vaccine strategies that do not require the use of live virus, such as virus-like particle (VLP) and DNA-based vaccines, have also been vigorously pursued in recent years. Studies have demonstrated that influenza VLP vaccination can confer homologous and heterologous protection from lethal challenge in a mouse model of infection. There have also been improvements in the formulation and production of vaccines following concerns over the threat of H5N1 influenza viruses. The use of novel substrates for the growth of vaccine virus stocks has been intensively researched in recent years, and several candidate cell culture-based systems for vaccine amplification have emerged, including production systems based on Madin-Darby canine kidney, Vero, and PerC6 cell lines. Such systems promise increased scalability of product, and reduced reliance on embryonated chicken eggs as a growth substrate. Studies into the use of adjuvants have shown that oil-in-water-based adjuvants can improve the immunogenicity of inactivated influenza vaccines and conserve antigen in such formulations. Finally, efforts to develop more broadly cross-protective immunization strategies through the inclusion of conserved influenza virus antigens in vaccines have led to experimental vaccines based on the influenza hemagglutinin (HA) stem domain. Such vaccines have been shown to confer protection from lethal challenge in mouse models of influenza virus infection. Through further development, vaccines based on the HA stem have the potential to protect vaccinated individuals against unanticipated pandemic and epidemic influenza virus strains. Overall, recent advances in experimental vaccines and in vaccine production processes provide the potential to lower mortality and morbidity resulting from influenza infection.

Swine influenza virus vaccines: to change or not to change-that's the question

Commercial vaccines currently available against swine influenza virus (SIV) are inactivated, adjuvanted, whole virus vaccines, based on H1N1 and/or H3N2 and/or H1N2 SIVs. In keeping with the antigenic and genetic differences between SIVs circulating in Europe and the US, the vaccines for each region are produced locally and contain different strains. Even within a continent, there is no standardization of vaccine strains, and the antigen mass and adjuvants can also differ between different commercial products. Recombinant protein vaccines against SIV, vector, and DNA vaccines, and vaccines attenuated by reverse genetics have been tested in experimental studies, but they have not yet reached the market. In this review, we aim to present a critical analysis of the performance of commercial inactivated and novel generation SIV vaccines in experimental vaccination challenge studies in pigs. We pay special attention to the differences between commercial SIV vaccines and vaccination attitudes in Europe and in North America, to the issue of vaccine strain selection and changes, and to the potential advantages of novel generation vaccines over the traditional killed SIV vaccines.

Endogenously expressed matrix protein M1 and nucleoprotein of influenza A are efficiently presented by class I and class II major histocompatibility complexes

Current influenza vaccines containing primarily hypervariable haemagglutinin and neuraminidase proteins must be prepared against frequent new antigenic variants. Therefore, there is an ongoing effort to develop influenza vaccines that also elicit strong and sustained cytotoxic responses against highly conserved determinants such as the matrix (M1) protein and nucleoprotein (NP). However, their antigenic presentation properties in humans are less defined. Accordingly, we analysed MHC class I and class II presentation of endogenously processed M1 and NP in human antigen presenting cells and observed expansion of both CD8+- and CD4+-specific effector T lymphocytes secreting gamma interferon and tumour necrosis factor. Further enhancement of basal MHC-II antigenic presentation did not improve CD4+ or CD8+ T-cell quality based on cytokine production upon challenge, suggesting that endogenous M1 and NP MHC-II presentation is sufficient. These new insights about T-lymphocyte expansion following endogenous M1 and NP MHC-I and -II presentation will be important to design complementary heterosubtypic vaccination strategies.

Development of retinol-binding protein 4 immunocolloidal gold fast test strip using high-sensitivity monoclonal antibodies generated by DNA immunization

DNA immunization is an efficient method for high-affinity monoclonal antibody generation. Here, we describe the generation of several high-quality monoclonal antibodies (mAbs) against retinol-binding protein 4 (RBP4), an important marker for kidney abnormality and dysfunction, with a combination method of DNA priming and protein boost. The mAbs generated could bind to RBP4 with high sensitivity and using these mAbs, an immunocolloidal gold fast test strip was constructed. The strip can give a result in <5 min and is very sensitive with a detection limit of about 1 ng/ml. A small-scale clinical test revealed that the result of this strip was well in accordance with that of an enzyme-labeled immunosorbent assay kit currently available on the market. Consequently, it could be useful for more convenient and faster RBP4 determination in the clinic.

Convalescent transfusion for pandemic influenza: preparing blood banks for a new plasma product?

Due to the potential of a severe pandemic to limit efficacy or availability of medical countermeasures, some researchers have begun a search for new interventions that could complement the planned antiviral‐ and vaccine‐based response to an influenza pandemic. One such countermeasure—the transfusion of pandemic influenza‐specific antibodies from surviving patients to the clinically ill—is the focus of this commentary. Passive immunotherapy, which includes the use of monoclonal antibodies (MoAbs), hyperimmune globulin, or convalescent plasma, had been used before the advent of antibiotics and has recently reentered the limelight due to the accelerating development of MoAb therapies against cancer, a number of microbes, allograft rejection, and a host of other conditions. After the plausible biologic mechanism and somewhat limited data supporting the efficacy for this modality against influenza are reviewed, safety and logistical concerns for utilization of this potential new product (fresh convalescent plasma against influenza [FCP‐Flu]) are discussed. FCP‐Flu could indeed prove useful in a response to a pandemic, but two necessary items must first be satisfied. Most importantly, more research should be conducted to establish FCP‐Flu efficacy against the current and other pandemic strains. Second, and also importantly, blood banks and donor centers should examine whether offering this new product would be feasible in a pandemic and begin planning before a more severe pandemic forces us to respond without adequate preparation.