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As the COVID-19 pandemic is intensifying globally, more and more people are pinning their hopes on the development of vaccines. At present, there are many research teams who have adopted different vaccine technology routes to develop 2019-nCoV vaccines. This article reviews and analyzes the current development and research status of 2019-nCoV vaccines in different routes, and explores their possible development in the future.
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Humans , Betacoronavirus , Coronavirus Infections , Pandemics , Pneumonia, Viral , Viral Vaccines , Therapeutic UsesABSTRACT
At present,there are no ideal drugs and measures in the treatment and prevention of toxoplasmosis.The develop-ment of safe,convenient,and strong protective nucleic acid vaccine is an important strategy for prevention and control of toxo-plasmosis.The rhoptry protein(ROP)is a large class of proteins secreted by Toxoplasma gondii.ROPs play an important role in the invasion of host cells,the formation of parsitophorous vacuole(PV)and the regulation of proliferation by T.gondii.Thus, ROPs become the most promising candidates of vaccine.In this paper,we summarize the important members of the ROPs,the expression vector and the immunogenicity and immunoprotection of the nucleic acid vaccine in animal experiments.
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Objective:To construct the recombinant DNA E.coli ghosts (EBGs) expressing Treponema pallidum adhesin Tp0751 (pcD/Tp0751-BG) and determine its immunocompetence in immunized mice,and provide a potential novel method for syphilis vaccine developing.Methods:The recombinant eukaryotic expression plasmid pcDNA3.1(+)/Tp0751 was constructed and loaded into empty EBGs to create pcD/Tp0751-BG.The loading rate was determined accordingly.Macrophages cell line RAW264.7 was transfected with pcD/Tp0751-BG,and the expression of recombinant Tp0751(rTp0751) protein was detected by Western blot(WB).For immuno-competence in mice,the female BALB/c mice were randomly divided into 6 groups,including three control groups,A (PBS),B (EBG),C (empty pcDNA),and experimental group D(naked pcD/Tp0751),E (pcD/Tp0751-BG) and F (pcD/Tp0751-BG+rTp0751).All the mice were immunized as indicated for three times by intramuscular injection at two weeks intervals.The levels of specific IgG in sera and SIgA in genital tract lavage fluid were measured by ELISA.Levels of lymphocyte proliferation and IFN-γ secretion in spleen cells were measured by CCK-8 Cell Counting Kit and ELISA as well,respectively.Results:The loading rate of pcD/Tp0751 to EBGs was 76.1%.WB showed that the target recombinant protein pcD/Tp0751 expressed in RAW264.7 cells was active with Tp-infected rabbit sera.The titers of specific IgG and SIgA in group D,E,F gradually increased to significantly higher level as compared to the control groups (P<0. 01),which reached its peak at wk 8 after last immunization(the titers of IgG and SIgA were 1 :102 400 and 1 :12 800 in group F,respectively). Higher levels of specific IgG and SIgA were observed in groups E and F as compared to group D after first boost (P<0. 01),with groups F higher than group E after last boost(P<0. 01). At wk 8 after the last boost,the stimulation index (SI) and levels of IFN-γ in group D,E,F were all significant higher than the control groups (P<0. 01), with group E and F higher than group D (P<0. 01),and group E higher than group F (P<0. 05). Conclusion: The recombinant DNA EBGs of T. pallidum adhesin Tp0751 (pcD/ Tp0751-BG) possesses the immunocompetence to induce not only strong mucosal and systemic humoral immune response but also systemic cellular immune response in BALB/ c mice. The heterologous boost can be more efficient than homologous boost during immunization process.
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Objective To research the immuno-protection of SJIR-2 DNA vaccine with nanometer microspheres a-gainst Schistosoma japonicum infection in mice. Methods To construct eukaryotic expression plasmid pEGFP-SJIR-2, identified by double digestion and sequenced delivery. The recombinant plasmid pEGFP-SJIR-2 was ex-tracted and was encapsulated into PLGA nanometer microspheres which were modified by CHS. 40 female BALB/c mice were randomly divided into 4 groups (n=10), each group of mice were injected with PBS, empty pEGFP plasmid, CHS-PLGA nanometer microspheres and CHS-PLGA-pEGFP-SJIR-2 nanometer microspheres 100 μg, re-spectively. Two weeks after the last immunization, each mouse was infected by cercaria of Schistosoma japonicum, sera of mice in each group were collected before each immunization and challenge infection. ELISA was used to de-tect the change of IgG in each group of micesera. 42 days later, all mice were sacrificed. The adult worms and eggs were collected and counted, and the worm and egg reduction rates were calculated as well. Results The recombi-nant plasmid pEGFP-SJIR-2 was successfully constucted, and there was significant difference in the numbers of worm and egg between CHS-PLGA-pEGFP-SJIR-2 group and PBS group ( P<0. 01 ) . The worm andegg reduction rates in CHS-PLGA-pEGFP-SJIR-2 group were 37. 36% and 46. 82% respectively. The IgG levels in mice sera of CHS-PLGA-pEGFP-SJIR-2 group were remarkably higher (P<0. 01) compared with PBS group. On the contrary, there was no significant difference between both pEGFP plasmid group and CHS-PLGA group in the numbers of worm and egg compared with PBS group. Conclusion SJIR-2 nanometer microspheres nucleic acid vaccine has some immuno-protection against Schistosoma japonicum infection in BALB/c mice,while it is worth further studying for it’ s potential value to be a candidate antigen molecule of Schistosoma japonicum vaccine.
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Because of the unique molecular structure and stable performance of yolk immunoglobulin ( IgY) , it has been a hot spot in the field of antibody research.As a new type of vaccine, nucleic acid vaccine has more advantages than most traditional vaccines, such as production cost, immunizing dose and immune protection.The approach combining the advantages of nucleic acid vaccine and IgY production in egg yolk and suck IgY has wide scope of application.In this re-view, we introduce a quick and inexpensive production method of IgY, namely, IgY produced by nucleic acid vaccine im-munization.
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AIM: DNA vaccines expressing protective domain of surface protective antigen A（spaA）of Erysipelothrix rhusiopathiae have been relatively ineffective at generating high-titer, long-lasting, neutralizing antibodies in murine models. METHODS: This paper report using a DNA vaccine expressing a fusion of the spaA protein and various elements, such as a secretion leader sequence from the highly expressed human gene encoding α1-antitrypsin (AAT), a highly soluble and stably folded domain from the rat cartilage oligomerization matrix protein (COMP), and three copies of the complement component, C3d3, to enhance the titers of neutralizing spaＡ-specific antibody. RESULTS: Analysis of titers of the antibody raised in vaccinated mice at different time points indicated that immunizations with the DNA expressing pcDNA3-AAT-COMP-spaAN-3C3d((pcD-ACSC)) had higher titers than pcDNA3-spaA_N(pcD-S) at weeks 4. Furthermore, the immune protective efficacy of the spaA-chimeras was demonstrated by lethal challenge with a virulent homologous strain 1249 against immunized mice. CONCLUSION: These results suggest that using a plasmid vector containing a strong heterologous signal sequence that mediate efficient antigen secretion in vivo and a fused piece of sequence improving antigens solubility, as well as C3d3, genetic adjuvant, could enhance the antibody responses level. This approach might be an efficient way to improve the antibody level of spaA_N DNA vaccination.
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An HA-1-DC nucleic-acid vaccine was constructed to induce anti-leukemia effect after hematopoietic stem cell transplantation (HSCT). DCs were generated from HSCT donors in vitro, and its immunologic activity was assayed by using flow cytometry and mixed lymphocytes reaction.HA-1 gene was electroporated into the cultured DCs to construct a DC nucleic-acid vaccine. After transfection for 48 h, the expression of HA-1 protein could be detected by using Western blot. The DCs were cultured with syngenic lymphocytes to induce specific cytotoxic T lymphocytes (CTLs).The cytoxicity of the CTLs was detected by LDH assay. The results showed that The DCs derived from peripheral blood monocytes (PBMCs) expressed the phenotype of DCs, and were effective in stimulating proliferation of the allogenic lymphocytes. After electroporating for 48-h, HA-1 protein was detected by using Western blot. The cytotoxity of inducing CTLs was higher than the control group. It was suggested that minor histocompatibility antigen HA-1 could be considered as a target of immunotherapy against leukemia after HSCT.
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Abstract Objective:To construct bmcella melitensis Br.melitensis genomic DNA expression library and study its immune effect.Meth-ods: Hind Ⅲ digested Br.melitensis genomic DNA fragments were cloned into pSV-?-Gal plasmds.The recombinant plasmids were transformedinto JM109 host bacteria. After large-scale isolation, the recombinant plasmids were inoculated into the quadriceps muscle of mice. In the 9thday after third boost immunization .agglutination antibodies against Br. melitensis and lymphocyte mitogenic ability of mice were determined. Re-sults : Expression library nucleic acid vaccine can induce the production of agglutination antibodies against Br. melitensis and stimulate the lym-phocyte porliferation primed by ConA. Conclusion:The genomic DNA expression library may provide a new vaccine against Br. melitensis infec-tion.
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Objective: To construct TCR V? nucleic acid vaccine. Methods: A fragment of TCR V? gene was amplified by RT- PCR from a human T lymphoma cell line, Jurkat, and cloned into eukaryotic expression plasmid pcDNA3 by gene recombination. After sequencing, the recombinant plasmid was transfected into SP2/0 cells and its expression was detected on mRNA level. BALB/c mice were immunized with pcDNA3 and the recombinant plasmid by intramuscular routes. Antiserum was collected and detected by immunocytochemistry method. Results: A fragment of TCR V? gene from Jurkat cells was obtained and proved to be identical to published sequence. A recombinant plasmid pcDNA3-TCR V? was comstructed. Its expression was detectable on mR- NA level after being transfected into SP2/0 cells. Antiserum from mice immunized with pcDNA3-TCR V? reacted strongly with Ju- rkat cells and SP2/0 cells transfected by pcDNA3-TCR V?, while shows no reaction on CEM cells expressing TCR?? and SP2/0 cells. Antisera from normal force and mice immunized with pcDNA3 were both negative on Jurkat cells. The results of immunocy- tochemistry indicated that BALB/c mice immunized with pcDNA3-TCR V? produced specific antibody to Jurkat TCR V?.Conclu sion: The TCR V? nucleic acid vaccine we constructed can induce humoral immunity.
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0.05). Conclusion pcDNA3.1/SjTs-1 induced the mucosal and systemic immune response and partial protection against the challenge of S.japonicum by the intranasal vaccinations of mice.
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Specific primers were designed according to published nucleotide sequence of FABP (fatty acid binding protein) gene in the GenBank database. The kozak sequence (CCACC) was introduced at the upstream of initiator. The total RNA was extracted from protoscoleces of Echinococcus granulosus (Inner Mongol isolate). The FABP gene cDNA fragment was amplified by RT-PCR and cloned into pMD19-T vector for sequencing and analyzing. The cloned FABP gene cDNA was with 402bp. The ORF encoded 133 amino acids. The amplified cDNA fragment was subcloned into pCDNA3.1(+)vector. The results showed that the nucleic acid vaccine candidate pcDNA-FABP-NM has been constructed.
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Objective:To discuss CTL response to the hepatitis B viral nucleic acid vaccine in mice.Methods:The recombinant plasmid containing HBV S gene was directly injected intramusculary into BALB/C mice.HBsAb in sera was checked with ELISA.The recombinant plasmid was transfected P815 cells by liposome and screened by G418.Splenocytes were isolated for investigating specific CTL response. Results:HBsAb in sera of mice was tested after pcDHBs injection.HBsAg was detected in culture medium of the transfected P815 cells. Compared mice injected with pcDNA3.1,the specific CTL cytotoxity activity of mice immunized with pcDHBs was significantly enhanced.Conclusion:HBV nucleic acid vaccine could stimulate humoral immunity and CTL response of the mice.
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Abstract Objective:To observe and confirm the specific humoral and cellurar immune responses induced by the nucleic acid vaccinesencoding HBV PreS2+S of subtypes adw and adr and encoding HBcAg in H-2b mice. Methods: Twenty-three C57BL/6 (H-2b) mice were ran-domly divided into four groups:group pJW4303(group P); group pJW4303/MHBs/adw(group W); group pJW4303/MHBs/adr(group R) andgroup pJW4303/MHBs/adr+pJW4303/HBc(group R+C) .The imunization method is that each mouse was injected(i.m) into the quadriceps femurs muscles with the corresponding 100?g(100?l) of plasmid DNA at 0,2,4 w.ELISA determined the level of anti-HBs and anti-HBc an-tibody in each mouse sera and the concentrations of IEN-? and IL-4 culture supernatant of spleen cells.Antigen specific proliferation of mousesplenocytes was measured by 3 H-TdR incorporating assay and the stimulation index(SI) was calculated.Results:After the last immunization,anti-HBs antibody had been detected in all mice of group W,group R and group R+C.The titers of anti-HBs were ranged from 22 329 to665.5 mU/ml.There are very significant differences between DNA vaccine groups (group W,group R,group R+C) and control group (groupP)(P0.05).Anti-HBs was first de-tected in group R+C.After the first immunization of nucleic acid vaccine of pJW4303/HBc,anti-HBc antibody appeared in all mice of groupR+C. Neither anti-HBs nor anti-HBc antibody appeared in all nice of group R+C.Neither anti-HBs nor anti-HBc was detected in group P.The stimulation index(SI) represent the capacity of antigen specific mouse proliferation of splenocytes. HBsAg-specific SIs of mouse splenocytesfrom group W,group R and group R+C is hipe than that in group P(P
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Objective:To discuss mice cellular immune response to the hepatitis C viral nucleic acid vaccine.Methods:Hepatitis C viral nucleic acid vaccine pSVL HCV/C+E 1 was inoculated BALB/C mice by subcutaneous injection.To detect the CTL activity of immune mice,Made the standard 4 hours lysis test by labeling the target cells with (Na) 2 51 CrO 4,which was prepared from the syngentic BALB/C mouse myeloma derived cell strain SP2/0 transfected by the eukaryotic expression recombinant plasmid pEGFP N 1 HCV/C+E 1.Results:The kill ratio of CTL is up to 40.7%.Conclusion:The result suggested hepatitis C viral nucleic acid vaccine could induce strong cellular immune response
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Objective To construct the nucleic acid vaccine(DNA vaccine) plasmid of the gag gene of the prevalent HIV-1 strains in China so as to develop a therapeutic AIDS vaccine against the HIV-1 strains, and to investigate the immune responses induced by HIV-1 DNA vaccine in mice. Methods The recombinant expression vector pCI-neo GAG was constructed by inserting HIV gag gene into the eukaryotic expression vector pCI-neo, which was identified by restrictive enzymes (Xba Ⅰ/Sal Ⅰ) digestion analysis and DNA sequencing. Balb/c mice were immunized with pCI-neo GAG or pCI-neo. Their sera were collected for the assay of the titer of anti-HIV antibody and IFN-? level by ELISA, and their splenic cells were isolated for detecting antigen-specific lymphoproliferative responses and specific cytotoxic T lymphocyte(CTL) response by MTT assay and LDH assay, respectively. Results Restrictive enzymes digestion analysis and DNA sequencing results revealed that the recombinant expression vector pCI-neo GAG had been constructed successfully. Both the anti-HIV antibody titer and the IFN-? level of mice immunized with the pCI-neo GAG were higher than those of mice immunized with pCI-neo (P