Antigens, Viral ; genetics ; Humans ; Mutation ; Orthomyxoviridae ; classification ; genetics ; immunology

Vaccination is the primary strategy for the prevention and control of pandemic influenza. Because influenza virus is highly variable across strains, universal influenza vaccines need to be developed to address this problem. This review describes the research progress in conserved epitopes of influenza virus, the advances in the research and development of universal influenza vaccines based on the relatively conserved sequences of NP, M2e, HA2, and headless HA, the mechanisms of cross-protection, and the methods to improve cross-protection.
Animals ; Cross Reactions ; Humans ; Orthomyxoviridae ; immunology ; Species Specificity ; Viral Proteins ; immunology ; Viral Vaccines ; genetics ; immunology

Animals ; DNA, Complementary ; genetics ; Genome, Viral ; Humans ; Influenza Vaccines ; genetics ; immunology ; Orthomyxoviridae ; genetics ; immunology ; RNA, Viral ; genetics

Virus-like particles (VLPs) are composed of multiple copies of one or more expressed recombinant viral structural proteins which spontaneously assemble into particles upon expression. VLPs are non infectious because they assemble without incorporating genetic material. VLPs have structural characteristics and antigenicity similar to the parental virus because they mimick the wild-type virus structure. Hence, they are recognized readily by the immune system which induces strong anti-viral immune responses to stop virus infection. VLPs have therefore shown dramatic effectiveness as candidate vaccines and diagnostic reagent for virus. Here, in order to provide reference to the research of influenza VLPs, we reviewed the current research progress of influenza VLPs, and discussed the characteristics associated with producing VLPs for influenza virus.
Animals ; Humans ; Influenza Vaccines ; genetics ; immunology ; Influenza, Human ; immunology ; virology ; Orthomyxoviridae ; genetics ; immunology ; physiology ; Viral Proteins ; genetics ; immunology ; Virion ; genetics ; immunology ; physiology ; Virus Assembly

The constant outbreaks of influenza in a global scale have aroused great concern all over the world. Vaccine has been the most effective and economic means against influenza. However, the broad tropism and high mutation of influenza viruses have limited the effectiveness of influenza vaccines. Current influenza virus vaccines provide effective protection against virus strains that are identical or highly similar to the vaccine strain. Once a highly mutated or new strain of influenza virus appears, the current vaccine would lose its effectiveness. Therefore, the development of a universal vaccine against highly mutated or new influenza virus subtypes has become a hot spot in the field of influenza vaccine research. The major methods of developing the universal influenza vaccine are to select a conserved protein of influenza virus as an antigen. At least three universal influenza vaccines have been tested in clinical trials. Moreover, changing the routes of vaccine immunization and immunization schemes could also improve the effect of heterosubtypic immunity. This review summarized the research progresses of universal influenza vaccines and provided our prospective on universal influenza vaccine research.
Animals ; Biomedical Research ; trends ; Humans ; Influenza Vaccines ; genetics ; immunology ; Influenza, Human ; immunology ; prevention & control ; virology ; Orthomyxoviridae ; genetics ; immunology ; Viral Proteins ; genetics ; immunology

The aim of this study is to develop the recombinant adenovirus vaccine (rAdV) candidates containing neuraminidase (NA) gene of H5N1 influenza virus and test in BALB/c mice the effect of cell-mediated immunity. In this study, two kind of NA gene (WtNA gene, the wild type; Mod. NA gene, the codon-modified type) derived from H5N1 influenza virus (A/Anhui/1/2005) were cloned and inserted respectively into plasmid of adenovirus vector, then the rAdV vaccines candidates (rAdV-WtNA and rAdV-Mod. NA) were developed and purified, followed by immunization intramuscularly (10(9) TCID50 per dose, double injection at 0 and 4th week) in BALB/c mice, the effect of cell-mediated immunity were analysed at 5th week. Results indicated that: (i) NA protein expression was detected in two rAdV vaccines candidates by Western blotting; (ii) the rAdV-Mod. NA vaccine could elicit more robust NA specific cell-mediated immunity in mice than that of rAdV-WtNA vaccine (P = 0. 016) by IFN-gamma ELIspot assay. These findings suggested rAdV-Mod. NA vaccine was a potential vaccine candidate against H5N1 influenza and worthy of further investigation.
Animals ; Blotting, Western ; Female ; Humans ; Immunity, Cellular ; genetics ; immunology ; Influenza A Virus, H5N1 Subtype ; genetics ; immunology ; Influenza Vaccines ; genetics ; immunology ; Mice ; Mice, Inbred BALB C ; Neuraminidase ; genetics ; immunology ; Orthomyxoviridae Infections ; immunology ; virology ; Polymerase Chain Reaction ; Random Allocation ; Viral Proteins ; genetics ; immunology

The desired effect of vaccination is to elicit protective immune responses against infection with pathogenic agents. An inactivated influenza vaccine is able to induce the neutralizing antibodies directed primarily against two surface antigens, hemagglutinin and neuraminidase. These two antigens undergo frequent antigenic drift and hence necessitate the annual update of a new vaccine strain. Besides the antigenic drift, the unpredictable emergence of the pandemic influenza strain, as seen in the 2009 pandemic H1N1, underscores the development of a new influenza vaccine that elicits broadly protective immunity against the diverse influenza strains. Cold-adapted live attenuated influenza vaccines (CAIVs) are advocated as a more appropriate strategy for cross-protection than inactivated vaccines and extensive studies have been conducted to address the issues in animal models. Here, we briefly describe experimental and clinical evidence for cross-protection by the CAIVs against antigenically distant strains and discuss possible explanations for cross-protective immune responses afforded by CAIVs. Potential barriers to the achievement of a universal influenza vaccine are also discussed, which will provide useful guidelines for future research on designing an ideal influenza vaccine with broad protection without causing pathogenic effects such as autoimmunity or attrition of protective immunity against homologous infection.
Adaptive Immunity ; Antigens, Viral/immunology ; *Cross Protection ; Genome, Viral ; Humans ; Immunity, Innate ; Influenza Vaccines/*immunology/therapeutic use ; Influenza, Human/*prevention & control ; Orthomyxoviridae/genetics/immunology ; Vaccines, Attenuated

Abstract: To develop novel live attenuated influenza vaccine, we explored the feasibility to attenuate influenza virus by codon deoptimization of NS1. According to the codon usage bias in influenza A virus, we designed and synthesized a condon-deoptimized NS gene by substituting codons of 110 amino acids in the NS1 gene of A/Puerto Rico/8/34(H1N1) with unpreferred synonymous codons. The influenza A virus with the codon deoptimized NS1 gene (deoNS virus) was rescued by reverse genetics. Plaque forming assay and virus growth curve showed that the growth of deoNS virus was reduced about 1000 times in MDCK cells compared to that of the wild-type virus. Intranasal inoculation with deoNS virus did not cause death or evident disease in infected BALB/c mice. Furthermore, the virus titer in the lungs of mice infected with deoNS virus was significantly lower (i.e. 100-1000 times) than that of wild-type virus. Our results indicated that influenza virus could be effectively attenuated by synonymous codon deoptimization of NS1 gene. This strategy will be useful to develop new attenuated candidates for the production of live attenuated influenza vaccines.
Animals ; Base Sequence ; Chick Embryo ; Codon ; genetics ; Influenza A virus ; genetics ; pathogenicity ; Influenza Vaccines ; immunology ; Mice ; Mice, Inbred BALB C ; Molecular Sequence Data ; Orthomyxoviridae Infections ; immunology ; prevention & control ; Recombination, Genetic ; Vaccines, Attenuated ; immunology ; Viral Nonstructural Proteins ; genetics ; Virulence ; genetics

Swine influenza viruses (SwIVs) cause considerable morbidity and mortality in domestic pigs, resulting in a significant economic burden. Moreover, pigs have been considered to be a possible mixing vessel in which novel strains loom. Here, we developed and evaluated a novel M2e-multiple antigenic peptide (M2e-MAP) as a supplemental antigen for inactivated H3N2 vaccine to provide cross-protection against two main subtypes of SwIVs, H1N1 and H3N2. The novel tetra-branched MAP was constructed by fusing four copies of M2e to one copy of foreign T helper cell epitopes. A high-yield reassortant H3N2 virus was generated by plasmid based reverse genetics. The efficacy of the novel H3N2 inactivated vaccines with or without M2e-MAP supplementation was evaluated in a mouse model. M2e-MAP conjugated vaccine induced strong antibody responses in mice. Complete protection against the heterologous swine H1N1 virus was observed in mice vaccinated with M2e-MAP combined vaccine. Moreover, this novel peptide confers protection against lethal challenge of A/Puerto Rico/8/34 (H1N1). Taken together, our results suggest the combined immunization of reassortant inactivated H3N2 vaccine and the novel M2e-MAP provided cross-protection against swine and human viruses and may serve as a promising approach for influenza vaccine development.
Animals ; Antibodies, Viral/blood ; Antigens, Viral/genetics/*immunology ; Body Weight ; Cross Protection/*immunology ; Disease Models, Animal ; Epitopes, T-Lymphocyte/genetics/immunology ; Female ; Influenza A Virus, H3N2 Subtype/genetics/*immunology ; Influenza Vaccines/*immunology ; Mice ; Mice, Inbred BALB C ; Orthomyxoviridae Infections/*immunology/mortality/pathology/prevention & control ; Peptides/genetics/*immunology ; Random Allocation ; Survival Analysis ; Vaccines, Synthetic/immunology ; Virus Replication

Rhesus monkeys with high specific H5N1 antibody were inoculated the second time with H5N1 virus, the result of the second time H5N1 inoculation and the effect of first time H5N1 inoculation on second inoculation was evaluated. Monkeys of NO. 3, NO. 4, NO. 5 were inoculated with H5N1 allantoic fluid and NO. 6 with noninfectious allantoic fluid by intratracheal thyrocricoid puncture. Three months later, NO. 4, NO. 5, NO. 6 monkeys were infected with 7 ml TCID50 10(4.875) H5N1 allantoic fluid and NO. 3 monkey with 7 ml noninfectious allantoic fluid at the same time by the same method. Clinical symptoms were recorded and antibody response was detected by ELISA. NO. 3, NO. 4, NO. 6 monkeys were killed after 72 h post infection and NO. 5 monkey was killed after 7 days post infection. Pathologic changes of the infected monkeys' lung were examined by HE staining,immunohistochemistry and the virus in lung was detected by RT-PCR. Results showed that NO. 3, NO. 4, NO. 5 monkeys still retained high level of specific antibody, H5N1 virus only could be detected in NO. 6 monkey's lung by immunohistochemistry and RT-PCR ,and the lung of NO. 6 monkey injured worst . It can be concluded that Rhesus monkeys inoculated with H5N1 avian influenza A virus at the first time could retain a high level of specific antibody in 90 days and the clinical symptom had almost recovered, the ability of Rhesus monkeys to resist second infection of H5N1 virus was enhanced notably at that moment.
Animals ; Antibodies, Viral ; blood ; immunology ; Enzyme-Linked Immunosorbent Assay ; Immunohistochemistry ; Influenza A Virus, H5N1 Subtype ; genetics ; immunology ; pathogenicity ; Macaca mulatta ; Monkey Diseases ; immunology ; pathology ; virology ; Orthomyxoviridae Infections ; blood ; immunology ; pathology ; Reverse Transcriptase Polymerase Chain Reaction