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

Hepatitis C virus (HCV) core protein is considered to be an attractive candidate for development of protective HCV vaccines. However, this protein may attenuate the induction of systemic immune responses due to its immunomodulatory properties. In this study, we constructed a HCV core gene-containing eukaryotic expression plamid pCI-C, and an in vivo-inducible prokaryotic expression plasmid pZW-C, and transformed the recombinant plasmids into an attenuated Salmonella typhimurium aroA strain SL7207. The resulting bacterial strains SL7207/pCI-C and SL7207/pZW-C were used to orally immunize BALB/c mice, and the immune responses specific to HCV core protein were assessed. Immunization with the recombinant bacteria SL7207/pCI-C led to a persistent drop in percentage of CD3 CD4 T cells, and induced a weak anti-core IgG production. Splenocytes from SL7207/pCI-C immunized mice developed a relatively weak proliferation response and inferior cytotoxic activity compared to those from the mice immunized with bacteria SL7207/pZW-C. Boost immunization with SL7207/ pCI-C yielded limited improvement in immune strength, while the boost with bacteria SL7207/pZW-C significantly enhanced the immune response. These results suggest that de novo synthesis of native HCV core protein may blunt the induction of immune responses. Attenuated S. typhimurium carrying HCV core protein could efficiently activate systemic cellular and humoral responses, and may be a promising strategy for the development of core-based HCV vaccines.
Animals ; Hepacivirus ; genetics ; immunology ; Mice ; Plasmids ; genetics ; Salmonella typhimurium ; genetics ; metabolism ; Vaccines, DNA ; immunology ; Viral Core Proteins ; genetics ; immunology ; Viral Hepatitis Vaccines ; genetics ; immunology

Animals ; Humans ; Vaccines, Virus-Like Particle ; genetics ; immunology ; Viral Vaccines ; genetics ; immunology ; Virus Diseases ; immunology ; prevention & control ; virology

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

BACKGROUNDTo observe the LMP2 specific cellular and humoral immune responses after immunization with recombinant adenovirus Ad-LMP2 in rhesus.

METHODSThe rhesuses were immunized with Ad-LMP2 through intra muscular injection in three groups, high dosage (4.5 x 10(11) VP/kg), medium dosage (1.5 x 10(11) VP/kg) and low dosage (0.5 x 10(11) VP/kg) groups. They were totally immunized six times at intervals of 5 days. The specific cellular immune responses were tested during the 7th week by ELISPOT after immunization. And the titers of anti-LMP2 antibody were tested by EIA throughout the period of immunization.

RESULTSLMP2 induced specific cellular and humoral immune responses in all three dosage group. The potency of immune responses was related with the dosage of immunization. Higher dosage elicited more potent immune response. Both the neutralizing antibody to adenovirus and anti-LMP2 antibody could be detected from 2 weeks after immunization. They would reach the peak during 3-4 weeks after immunization, then declined during the 7th week after immunization.

CONCLUSIONThe recombinant adenovirus LMP2 could induce specific cellular and humoral responses in rhesus after immunization.

Adenoviridae ; genetics ; Animals ; Antibodies, Viral ; blood ; Antibody Formation ; immunology ; Female ; Immunization ; methods ; Macaca mulatta ; Male ; Recombinant Fusion Proteins ; genetics ; immunology ; T-Lymphocytes, Cytotoxic ; immunology ; Vaccines, DNA ; genetics ; immunology ; Viral Matrix Proteins ; genetics ; immunology ; Viral Vaccines ; genetics ; immunology

To enhance the immuogenicity of DNA vaccines expressing the GP5 protein of Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), the tegument protein VP22 (encoded by VP22 gene) of Bovine Herpesvirus 1 (BHV-1), which has been demonstrated to exhibit the unusual protein transduction property, was fused to N-terminus of GP5 of DNA vaccine construct pCI-ORF5M, resulting in pCI-VP22-ORF5M expressing VP22-GP5 fusion protein. The expression of VP22-GP5 fusion protein was confirmed by both indirect immunofluorescence assay (IFA) and Western blot. To investigate its immunogenicity, BALB/c mice were immunized with the fusion expression plasmid pCI-VP22-ORF5M and non-fusion expression plasmid pCI-ORF5M, respectively. The GP5-specific ELISA antibodies, neutralizing antibodies and lymphocyte proliferative responses were evaluated at various time points after primary immunization. The results showed that GP5-specific ELISA antibodies, neutralizing antibodies, and lymphocyte proliferative responses induced by DNA vaccine pCI-VP22-ORF5M were higher significantly than those of DNA vaccine pCI-ORF5M, indicating that fusion expression with BHV-1 VP22 significantly enhances the immuogenicity of DNA vaccine expressing the PRRSV GP5 protein, and that this strategy may also be useful to develop more efficient DNA vaccines against other pathogens.
Animals ; Antigens, Viral ; genetics ; immunology ; Artificial Gene Fusion ; Female ; Mice ; Mice, Inbred BALB C ; Porcine Reproductive and Respiratory Syndrome ; prevention & control ; Random Allocation ; Vaccines, DNA ; genetics ; immunology ; Viral Envelope Proteins ; genetics ; immunology ; Viral Structural Proteins ; genetics ; Viral Vaccines ; genetics ; immunology

In order to research immunogenicity of the recombinant rVP2-IL-2 fusion protein, we obtained the rVP2-IL-2 fusion protein using Pichia pastoris expression system, and then evaluated its potential to induce immune responses in chicken. The effect was determined in the form of protective anti-IBDV VP2 titers, antibodies (IgG1 and IgG2a), lymphocyte proliferation, the levels of interferon-gamma and interleukin-4 cytokines, and challenge experiment. Antibody titers and proliferation lymphocyte level suggested that the fusion protein could elicit specific humoral immune and cellular immune responses, antibody sub-type results indicated that the rVP2-IL-2 fusion protein induced secretion both of IgG1 and IgG2a. The seem result elicited from cytokines ELISA test, secretion of both of Th1 (gamma-IFN) and Th2 (IL-4) were induced by the rVP2-IL-2 fusion protein. Challenge experiment result shown that chicken immunized the rVP2-IL-2 fusion protein obtained 85% protection. These results confirm that the fusion protein enhances the protection against IBDV through both humoral and cell-mediated immunity, and thus could serve as a candidate for the development of IBDV subunit vaccine.
Animals ; Antibodies, Viral ; biosynthesis ; blood ; Chickens ; immunology ; Immunoglobulin G ; blood ; Interleukin-2 ; biosynthesis ; genetics ; Pichia ; genetics ; metabolism ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; immunology ; Th1 Cells ; immunology ; Th2 Cells ; immunology ; Vaccines, Subunit ; immunology ; Viral Structural Proteins ; biosynthesis ; genetics ; Viral Vaccines ; immunology

The respiratory syncytial virus (RSV) belongs to the family Paramyxoviridae and subfamily Pneumovirinae. The RSV can cause acute infections of the lower respiratory tract in infants. The F gene of the RSV is a conservative gene and varies only slightly in its expression. Few studies focusing on the variability of the F gene have been carried out. F protein (fusion glycoprotein) is a transmembrane glycoprotein that mediates fusion and penetration between the virus and host cells. Neutralizing antibody against the F protein can protect against infection by RSV subtypes A and B. Hence, F protein has become the main target for the development of a monoclonal antibody and vaccine against the RSV. An effective vaccine is not available, so a monoclonal antibody against F protein is now the most important method to reduce the morbidity and severity associated with RSV infection in high-risk children. However, a monoclonal antibody can lead to the production of drug-resistant strains of the RSV. This review focuses on genetic variation of the F gene of the RSV as well as progress in the development of a monoclonal antibody against F protein and a vaccine in the last decade.
Animals ; Antibodies, Monoclonal ; immunology ; Humans ; Respiratory Syncytial Virus Infections ; immunology ; prevention & control ; virology ; Respiratory Syncytial Viruses ; genetics ; immunology ; Viral Fusion Proteins ; genetics ; immunology ; Viral Vaccines ; genetics ; immunology

This study aimed to develop an effective experimental vaccine against highly pathogenic H5N1 Avian Influenza (HPAI) virus and to optimize their immunization programs. As reported previously, various DNA-based or recombinant vaccinia viral(Tiantan)-based H5N1 vaccine candidates, which containing a single cistronic construct (HAop, or NAop) or a bicistronic construct (HAop/M2 or NAop/M1) of H5N1 influenza virus (Anhui strain) were constructed and characterized in our lab. In this study, we further analysed the immunogenicity in mice of these vaccine candidates by various protocols (single or combined immunization). Our results showed that: comparing with immunization with DNA-based or rTTV-based H5N1 vaccine only, combined DNA-based with rTTV-based H5N1 vaccine immunization via prime-boost strategy enhanced immune response significantly against multi-H5N1 antigens detected by hemagglutination inhibition (HI) assay, NA- or M1- or M2-specific antibody detection, and micro-neutralizing antibody test and IFN-gamma ELISpot assay. Priming with DNA-based vaccine induced higher level of humoral response against HA or NA antigen than priming with rTTV-based vaccine; In contract, M1 and M2-specific antibody levels were higher among that of priming with rTTV -based vaccine. These findings provide a basis for further development of novel H5N1 vaccines and for the optimization of the immunization programs of combined multi-antigens vaccine candidates.
Animals ; Antigens, Viral ; genetics ; immunology ; Female ; Immunization ; methods ; Influenza A Virus, H5N1 Subtype ; genetics ; immunology ; Influenza Vaccines ; genetics ; immunology ; Mice ; Mice, Inbred BALB C ; Vaccination ; methods ; Vaccines, DNA ; genetics ; immunology ; Vaccines, Synthetic ; genetics ; immunology ; Vaccinia ; genetics ; immunology

The fusion protein (F) gene of Newcastle disease virus was amplified by polymerase chain reaction (PCR) from the recombinant plasmid pVAX1-F, and subcloned into eukaryotic expression vector pmcDNA3. 1+. The F gene was identified by sequencing. The recombinant plasmid was transformed into attenuated Salmonella typhimurium SL7207, and the recombinant was designated as SL7207 (pmcDNA3. 1-F). In vitro and in vivo experiments showed that the plasmid stability of pmcDNA3. 1-F was apparently higher than that of pcDNA3. 1-F in SL7207. In order to compare the immune response induced by these two re combinant bacteria, BALB/c mice were immunized orally with them at the dosage of 2 x 10(9) CFU respectively. Both SL7207(pcDNA3. 1-F) and SL7207(pmcDNA3. 1-F) initiated F-specific serum and mucosal antibodies in immunized mice. Furthermore, 4-day-old SPF chickens were immunized with SL7207(pcDNA3. 1-F) and SL7207(pmcDNA3. 1-F) at the dosage of 5 x 10(9) CFU and boosted two weeks later with the same dosage. Humoral and intestinal mucosal immune responses were observed and their levels were significantly higher than that of negative and positive controls. The result of protective efficacy showed that the chickens immunized with SL7207(pmcDNA3. 1-F) had the protective rate of 70.0%, higher than that of the SL7207 (pcDNA3. 1-F) with 50.0%. In summary, the DNA vaccine delivered by attenuated Salmonella typhimurium has good immunogenicity. A novel mucosal DNA vaccine has been developed and could be useful for controlling the infection and epidemic of Newcastle disease in the poultry.
Animals ; Chickens ; Female ; Immunization ; Mice ; Mice, Inbred BALB C ; Newcastle disease virus ; immunology ; Plasmids ; Salmonella typhimurium ; genetics ; Vaccines, Attenuated ; immunology ; Vaccines, DNA ; immunology ; Viral Vaccines ; immunology