ABSTRACT
Hepatitis B virus core protein can self-assemble into icosahedral symmetrical viral-like particles (VLPs) in vitro, and display exogenous sequences repeatedly and densely on the surface. VLPs also have strong immunogenicity and biological activity. When the nanoparticles enter the body, they quickly induce specific humoral and cellular immune responses to exogenous antigens. In this study, we designed an HBc-VLPs that can be coupled with antigens at specific sites, and developed a set of efficient methods to prepare HBc-VLPs. Through site-specific mutation technology, the 80th amino acid of peptide was changed from Ala to Cys, a specific cross-linking site was inserted into the main immunodominant region of HBc-VLPs, and the prokaryotic expression vector pET28a(+)-hbc was constructed. After expression and purification, high purity HBc(A80C) monomer protein was assembled into HBc-VLPs nanoparticles in Phosphate Buffer. The results of particle size analysis show that the average particle size of nanoparticles was 29.8 nm. Transmission electron microscopy (TEM) showed that HBc-VLPs formed spherical particles with a particle size of about 30 nm, and its morphology was similar to that of natural HBV particles. The influenza virus antigen M2e peptide as model antigen was connected to Cys residue of HBc-VLPs by Sulfo-SMCC, an amino sulfhydryl bifunctional cross-linking agent, and M2e-HBc-VLPs model vaccine was prepared. The integrity of HBc-VLPs structure and the correct cross-linking of M2e were verified by cell fluorescence tracing. Animal immune experiments showed that the vaccine can effectively stimulate the production of antigen-specific IgG antibody in mice, which verified the effectiveness of the vaccine carrier HBc-VLPs. This study lays a foundation for the research of HBc-VLPs as vaccine vector, and help to promote the development of HBc-VLPs vaccine and the application of HBc-VLPs in other fields.
Subject(s)
Animals , Mice , Hepatitis B Core Antigens , Genetics , Allergy and Immunology , Immunity, Cellular , Allergy and Immunology , Immunoglobulin G , Blood , Mice, Inbred BALB C , Vaccines, Virus-Like Particle , Genetics , Allergy and ImmunologyABSTRACT
Objective:To develop a host-vector balanced lethal system of attenuated Salmonella typhinurium secreted effector K1 mutant,and an live vaccine vector which stably carries exogenous genes. Methods:We constructed SL1344ΔsseK1Δasd mutant strain by recombinant suicide plasmid( pREΔasd) ,and screened by two-step method,transformed pYA3493 plasmid containing the asd gene without resistance electric into the mutant strain of SL1344ΔsseK1Δasd, then the recombinant strain SL1344ΔsseK1Δasd (pYA3493) was constructed successfully. Results:The results of PCR and sequencing showed that SL1344ΔsseK1Δasd(pYA3493)was constructed successfully. Further studies had shown that the serotype of the recombinant strain was identical to the parent SL1344ΔsseK1 and wild SL1344 strains,and the mutant was stable with the recombinant Δasd gene in vitro. It was found that the re-combinant strain had displayed identical growth profile and biochemical characteristics compared with the parent SL1344ΔsseK1 strain and wild SL1344 strain. The oral challenge of bacteria in mice revealed that LD50 of the recombinant strain was 5. 24×108 CFU,and the toxicity reduced to about 0. 048%;the immunoprotective effect assay showed that the protection rate infected with wild strain of Salmonella typhimurium was 62. 5% on the 17th day post-immunization,which was identical to the parent SL1344ΔsseK1. Conclusion:These results show that the secreted effector K1 gene deleted mutant host-vector balanced lethal system of Salmonella typhimurium SL1344 strain has been successfully constructed,and genetic stability,significantly reduced virulence,which has laid a foundation for developing potential oral live vaccin vector to express foreign genes.
ABSTRACT
Objective:To develop a host-vector balanced lethal system of attenuated Salmonella typhinurium secreted effector K1 mutant,and an live vaccine vector which stably carries exogenous genes. Methods:We constructed SL1344ΔsseK1Δasd mutant strain by recombinant suicide plasmid( pREΔasd) ,and screened by two-step method,transformed pYA3493 plasmid containing the asd gene without resistance electric into the mutant strain of SL1344ΔsseK1Δasd, then the recombinant strain SL1344ΔsseK1Δasd (pYA3493) was constructed successfully. Results:The results of PCR and sequencing showed that SL1344ΔsseK1Δasd(pYA3493)was constructed successfully. Further studies had shown that the serotype of the recombinant strain was identical to the parent SL1344ΔsseK1 and wild SL1344 strains,and the mutant was stable with the recombinant Δasd gene in vitro. It was found that the re-combinant strain had displayed identical growth profile and biochemical characteristics compared with the parent SL1344ΔsseK1 strain and wild SL1344 strain. The oral challenge of bacteria in mice revealed that LD50 of the recombinant strain was 5. 24×108 CFU,and the toxicity reduced to about 0. 048%;the immunoprotective effect assay showed that the protection rate infected with wild strain of Salmonella typhimurium was 62. 5% on the 17th day post-immunization,which was identical to the parent SL1344ΔsseK1. Conclusion:These results show that the secreted effector K1 gene deleted mutant host-vector balanced lethal system of Salmonella typhimurium SL1344 strain has been successfully constructed,and genetic stability,significantly reduced virulence,which has laid a foundation for developing potential oral live vaccin vector to express foreign genes.
ABSTRACT
Objective:To provide a potential platform for transferring specific antigen against fish bacterial diseases based on attenuated Lm (EGDe-ΔactA/ΔinlB).Methods: Attenuated Lm (EGDe-ΔactA/ΔinlB) was used to express outer membrane protein K (Ompk),a conserved and effective vaccine candidate in vibrio.The identification of recombinant strains and detection of antigen genes were operated with PCR and RT-PCR,respectively.Results: The results of PCR showed that Lm-Ompk (L-O),Lm-Lmo0576-Ompk (L-L-O) and Lm-P-Ompk (L-P-O) were constructed successfully.The identity of foreign gene was 100％ compared with sequence of NCBI.The analysis of transcription showed that the expressions of Ompk in L-O,L-L-O and L-P-O were significant (P<0.001).Moreover,the expression of Ompk in the condition of antibiotic was higher than that in the BHI without antibiotic (P<0.05).Conclusion: Lm-Ompk (L-O),Lm-Lmo0576-Ompk (L-L-O) and Lm-P-Ompk (L-P-O) were constructed successfully.
ABSTRACT
In order to develop a recombinant attenuated Salmonella typhimurium as oral live vaccine vector, we constructed recombinant plasmid pYA-sopENt100 by replacing the trc promoter with the sopE promoter and secretion signal sequence sopENt100 of Salmonella typhimurium on the basis of plasmid pYA3493. Then, the complementary plasmid pYA-sopENt100 was transformed into ΔcrpΔasdSL1344 by electroporation to generate attenuated Salmonella typhimurium type III secretion system ΔcrpΔasdSL1344 (pYA-sopENt100). We further characterized ΔcrpΔasdSL1344 (pYA-sopENt100). We also constructed a recombinant strain ΔcrpΔasdSL1344 (pYA-sopENt100-egfp) that harbored the reporter gene-enhanced green fluorescent protein (egfp) gene. Vero cells were infected with ΔcrpΔasdSL1344 (pYA-sopENt100-egfp) and the ability of delivery foreign antigens was tested via Western blotting analysis. The results of PCR, enzyme digestion and sequencing showed that the ΔcrpΔasdSL1344 (pYA-sopENt100) type III secretion system was constructed successfully. The serotype of ΔcrpΔasdSL1344 (pYA-sopENt100) was identical to ΔcrpΔasdSL1344 and SL1344. Compared with wild strain SL1344, the biochemical characteristics of ΔcrpΔasdSL1344 (pYA-sopENt100) had obvious change, but it was basically the same with ΔcrpΔasdSL1344. The growth speed was much slower than that of the wild strain SL1344. The chicken virulence test (LD₅₀) showed that the virulence of ΔcrpΔasdSL1344 (pYA-sopENt100) was 7×10⁴ times lower than SL1344. In addition, we observed the 37 kDa SopENt100-egfp protein in the cultured supernatant of ΔcrpΔasdSL1344 (pYA-sopENt100-egfp) strain by Western blotting analysis. However, both the 37 kDa SopENt100-egfp protein and 27 kDa EGFP protein were detected in ΔcrpΔasdSL1344 (pYA-sopENt100-egfp)-infected Vero cells. These results demonstrated that the recombinant Salmonella typhimurium type III secretion system ΔcrpΔasdSL1344 (pYA-sopENt100) was successfully constructed, and it should be used as a live vaccine vector for expressing foreign genes.
Subject(s)
Animals , Mice , Bacterial Proteins , Genetics , Chlorocebus aethiops , Plasmids , Promoter Regions, Genetic , Salmonella typhimurium , Genetics , Type III Secretion Systems , Genetics , Vaccines, Attenuated , Genetics , Vero Cells , VirulenceABSTRACT
Objective: To develop an oral live vaccine vector which stably carries exogenous genes.Methods:SL1344ΔsipBΔasd host-vector balanced lethal system was constructed by the method of recombinant suicide plasmid-mediated allelic exchange on the basis of attenuated Salmonella typhinurium SL1344ΔsipB.Then,the biological characteristics of SL1344ΔsipBΔasd was analyzed.Results:The results showed that the mutant was stabile with the Δasd gene in vitro;the serotype and growth rate of SL1344ΔsipBΔasd strain was almost same as the parent SL1344ΔsipB and SL1344 strain.And the mutant strains remain swim ming zones.Virulence test in mice showed that the virulence of SL1344ΔsipBΔasd which carried complementary plasmid pYA3493 by electro-transformation decreased by 1.4%compared with SL1344.Conclusion: These results showed that the SL1344ΔsipBΔasd mutant was successfully constructed.It is likely that this mutant should be used as a live vector to express foreign genes.
ABSTRACT
Objective:In order to develop an oral live vaccine vector of swine that can stably carry exogenous genes.Methods:Mutant ΔcrpΔcyaΔasdC78-1 was constructed by the method of suicide plasmid pREasd-mediated bacteria homologous recombination on the basis of attenuated Salmonella choleraesuisΔcrpΔcyaC78-1.Complementary plasmid pYA3493 with asd was electrotransformed into the mutant,and thenΔcrpΔcyaΔasdC78-1(pYA3493) host-vector balanced lethal system was constructed.Its biological characteristics were analyzed further.Results:The results of PCR and sequencing showed thatΔcrpΔcyaΔasdC78-1(pYA3493) was constructed suc-cessfully.Biological characteristics showed that the serotype of ΔcrpΔcyaΔasdC78-1(pYA3493) was identical to ΔcyaΔasdC78-1 and vaccine strain C500 and it can stably carry theΔasd gene in vitro;its growth speed was a little slower than ΔcrpΔcyaC78-1 strain,but both of their growth speeds were significantly slower than vaccine strain C500;the biochemical characteristics of ΔcrpΔcyaΔasdC78-1 ( pYA3493 ) were basically the same with ΔcrpΔcyaC78-1 strain.Oral virulence test in mice showed that the virulence ofΔcrpΔcyaΔasdC78-1 ( pYA3493 ) was similar with ΔcrpΔcyaC78-1, but its median lethal dose is 412 times of vaccine strain C500.Conclusion:These results demonstrated that attenuated Salmonella choleraesuisΔcrpΔcyaΔasdC78-1(pYA3493) strain had the potential to be used as an oral live vaccine vector for expressing foreign genes efficiently.
ABSTRACT
Listeriamonocytogenes is a facultative intracellular bacterium that enters professional antigen presenting cells , presents passenger antigens to the major histocompatibility complex class I and II pathways ,then elicits CD+4 and CD+8 T-cell-mediated immune responses .It was demonstrated that attenuated Listeriamonocytogenes as a novel live vaccine vector in deliv-ering tumor antigens of cervical cancer and melanoma etc .,could induce strong protective immune response ,and shows effec-tive antitumor immunotherapeutics .This review discussed the characteristics of immune responses elicited by Listeria monocy-togenes ,and the progress of its antitumor immunotherapeutics as delivery vaccine vector .
ABSTRACT
In order to develop a safer vaccine strain exploit Salmonella Pullorum vaccine strain as a live vaccine vector.Methods:AΔcrpΔasd mutant of S.pullorum C79-13 strain was constructed and it was developed E.coli donor strain mutant was generated through the two-step method introduced by χ7213 ( pREΔasd) was conjugated with the recipient of C 79-13Δcrp.The C79-13ΔcrpΔasd the transduction of recombinant suicide plasmid .Results:PCR and sequencing results showed that ΔsipBSL1344 was suc-cessfully constructed.The further study indicated that foreign DAP must be supplied for the ΔcrpΔasd mutant to grow,in addition,the asd gene was transmitted stably .Compared with C79-13 strain,the O antigens was identical to C79-13 strain,but the growth velocity was reduced significantly ,significantly reduced virulence .Conclusion: The ΔcrpΔasd mutant can accept asd+plasmid to construct host-vector balance lethal system , and this system can be used to express foreign gene efficiently and to develop potential oral multivalent vaccines.
ABSTRACT
In this study ,a wild type Salmonella typhimurium (S .typhimurium) strain was isolated and identified in Hong Kong (S129) ,then the asdA gene was knocked out and replaced with kanamycin resistant gene in a Salmonella typhi-murium strain S129 using the λ RED-mediated recombination method .The constructed mutant asdAΔS129 was validated by culturing in the presence or absence of 2 ,6-diaminopimelic acid (DAP) growth in vitro and evaluating its virulence in BALB/c mice challenge assay .Therefore ,this study has demonstrated that an asdA mutant Salmonella typhimurium has been success-fully constructed .
ABSTRACT
Objective To investigate the antigenicity of foreign antigen in recombinant vaccinia virus (VACV) after elimination of B8R,and provide help to improve the efficacy of VACV-based vaccines,and provide guidance for vaccine design.Methods Transfer vector pSC11-OVA was generated,and OVAgene was in,rted into VACV with B8R deletion.The biological characteristics of recombinant VACV was investigated in vitro,and the immune responses against OVA were tested in vivo.Results The plague phenotypes and growth of wcombinant VACV and its parental strains were essentially identical.Cellular immuneresponse against OVA was augmented in mice infected with B8R-deleted recombinant VACV when comparedwith those infected with B8R-intact recombinant VACV.Conclusion Deletion of B8R and insertion of OVAdoes not affect the biological characteristics of VACV.Immunogenicity of exogenous target antigens can beimproved in VACV with B8R deficiency.Deletion of dominant epitopes may provide a vector with more efficiency for vaccines and gene therapy.
ABSTRACT
Streptococcus gordonii is a nonpathogenic gram-positive commensal bacterium and component of the normal microbial flora of the human oral cavity. It is suitable to be as a mucosa vaccine vector due to its special bionomics. knowing the bionomics of Streptococcus gordonii,the general expressing system,and the application of it in mucosa vaccine,will provid important reference for the further development of its mucosa vaccine.