mRNA technology for the development of vaccines against infectious diseases / 中华微生物学和免疫学杂志

The mRNA-based vaccine technology is gradually developed as one of the new vaccine technologies in recent years. The technology is becoming more mature in terms of its stability and efficient delivery. Antigens encoded by mRNA vaccines are expressed in the cytoplasm and can induce the activation of both B cell responses and T cell cytotoxicity against infectious pathogens. In addition, the simple production process of synthetic mRNA vaccines can facilitate rapid response to emerging infectious diseases such as 2019-nCoV infection. In order to understand the current status of mRNA vaccine research and development for infectious diseases as well as providing reference for the development of clinically applicable mRNA vaccine against 2019-nCoV pandemic, this paper mainly reviewed the structural characteristics, advantages and challenges of mRNA vaccines and the current situation of vaccine research application in infectious diseases.

Identification of role of PI3K in mediating necroptosis of L929 cells induced by tumor necrosis factor alpha / 军事医学

Objective To identify the role of phosphatidylinositol-3-kinase(PI3K) in mediating necroptosis induced by tumor necrosis factor alpha (TNFα) and the involved mechanism.Methods Knockdown of p110α,receptor-interacting protein 1(RIP1) or both p110αand RIP1 was mediated by the specific short hairpin RNA (shRNA) lentivirus and verified by RT-PCR or Western blotting .In addition , Western blotting was used to detect phosphorylation of mixed lineage kinase domain-like protein(MLKL) and protein kinase B(AKT) or tetramerization of MLKL.Cell death was measured by micros-copy and flow cytometry.Results AKT phosphorylation and TNFα-induced necroptosis of L929 cells were suppressed by the inhibitors of PI3K or AKT, as well as p110αknockdown.Moreover, RIP1 knockdown did not inhibit L929 cell death induced by TNFαplus Z-VAD, but the RIP1-independent necroptosis was inhibited by p 110αknockdown.In addition, p110αknockdown suppressed MLKL phosphorylation and tetramerization induced by TNFαwith Z-VAD in L929 cells. Conclusion PI3K mediates necroptosis of L929 cells induced by TNFαby activating AKT and MLKL, respectively.

Construction and eukaryotic expression of PVAX1-hPV58mE6E7fcGB composite gene vaccine / 生物医学工程学杂志

To construct and express a composite gene vaccine for human papillomavirus 58(HPV58)-associated cervical cancer, we inserted HPV58mE6E7 fusion gene into pCI-Fc-GPI eukaryotic expression vector, constructing a recombinant plasmid named pCI-sig-HPV58mE6E7-Fc-GPI. Then we further inserted fragment of sig-HPV58mE6E7Fc-GPI into the novel vaccine vector PVAX1-IRES-GM/B7, constructing PVAX1-HPV58mE6E7FcGB composite gene vaccine. PVAX1-HPV58mE6E7FcGB vaccine was successfully constructed and identified by restriction endonuclease and sequencing analysis. Eukaryotic expression of fusion antigen sig-HPV58mE6E7-Fc-GPI and molecular ad-juvant GM-CSF and B7. 1 were proved to be realized at the same time by flow cytometry and immunofluorescence. So PVAX1-HPV58mE6E7FcGB can be taken as a candidate of therapeutic vaccine for HPV58-associated tumors and their precancerous transformations.

Prokaryotic expression, purification and antigenicity identification of mouse VEGFR2 extracellular 1-4 IgG-like domains / 南方医科大学学报

<p><b>OBJECTIVE</b>To obtain 1-4 IgG-like domains of mouse vascular endothelial growth factor receptor 2 (VEGFR2) fusion protein (mVEGFR2D1-4/GST) and identify its antiginicity and biological activity.</p><p><b>METHODS</b>The gene of mVEGFR2D1-4 was amplified by RT-PCR from 14-days embryos of Balb/c mice. The PCR product was cloned into pET-42a prokaryotic expression vector to construct the recombinant plasmid pET-42a-mVEGFR2D1-4, which was transformed into E. coli BL21 (DE3) strain for mVEGFR2D1-4/GST expression. The fusion protein was identified by SDS-PAGE and Western blotting, and the antigenicity of the protein purified by affinity chromatography was characterized by ELISA. The VEGF blocking effect of the purified protein in human umbilical vein endothelial cells (HUVECs) were evaluated in in vitro cell cultures.</p><p><b>RESULTS</b>The mVEGFR2D1-4 gene was obtained, which had an identical sequence to that retrieved in GenBank. The prokaryotic expression vector for mVEGFR2D1-4 was successfully constructed as confirmed by enzyme digestion and DNA sequencing. Both Western blotting and ELISA demonstrated the antigenicity of the purified mVEGFR2D1-4 fusion protein, which obviously blocked the effect of VEGF in promoting HUVEC proliferation in vitro.</p><p><b>CONCLUSION</b>The mVEGFR2D1-4/GST fusion protein obtained shows a strong antigenicity and biological activity to facilitate further study of active anti-tumor immunotherapy targeting VEGFR2.</p>

Influence of electroporation on immunogenicity of the DNA vaccine pVAX-tG250FcGB / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the influence of electroporation on the immunogenicity of the DNA vaccine pVAX- tG250FcGB.</p><p><b>METHODS</b>The DNA vaccine pVAX-tG250FcGB was constructed by inserting the coding gene of tG250 fusion genes into the expression vector pVAX. The DNA vaccine was delivered in BALB/c mouse by electroporation or intramuscular injection, and the induced antigen specific immune responses were compared.</p><p><b>RESULTS</b>The vaccine delivered by electroporation and intramuscular injection both induced immune responses in BALB/c mouse, but electroporation produced an obviously stronger effect than intramuscular injection.</p><p><b>CONCLUSION</b>Electroporation-mediated DNA vaccine delivery can produce strong immune response in mice and is an effective means for studying the immunogenic effect of DNA vaccine pVAX-tG250FcGB.</p>

Preliminary observation on antitumor effect of HPV58 composite DNA vaccine / 中华妇产科杂志

Objective To initially observe the antitumor immune of PVAX1-HPV58mE6E7FcGB composite DNA vaccine.Methods Before detecting immune effect of the vaccine,the B16-HPV58E6E7 tumor cell line was built which could steadily express HPV58E6E7 fusion gene.Then,HPV58E6E7-GST fusion protein as an antigen was expressed and purified.Before or after immunized with the vaccine,the C57BL/6 mice were challenged by B16-HPV58E6E7 cells.Anti-tumor transplantation and tumor growth inhibition experiment were performed to observe prevention and treatment effects on the vaccine.Specific humoral and cellular immune responses in the immunized mice were detected by ELISA,enzyme linked immunospot assay (ELISPOT) and cytotoxic T lymphocyte (CTL) method.Results In the anti-tumor transplantation experiment,tumor formation rate was only 9/15 in the mice which were immunized by PVAX1-HPV58mE6E7FcGB vaccine,time before tumor formation was the longest [(13.6 ± 1.7) days] and tumor growth was the slowest in the vaccine group.In tumor growth inhibition experiment,inhibition rate reached 81.4％ in the vaccine group.Except tumor formation rate,all data in the vaccine group was superior to the pure antigen PVAX1-HPV58mE6E7Fc group (P ＜ 0.05).Humoral immune effect showed that both the vaccine and the pure antigen could induce specific antibody in the immunized mice,and the highest titer were 1 ∶ 25600 and 1 ∶ 12800,respectively.Although there was not significant difference of antibody titer between the vaccine and the pure antigen group (P ＞ 0.05),the number of activated T cells in the vaccine group was almost four times as that in the pure antigen group [(219 ±34)/4 × 105 spleen lymphocytes versus (55 ±25)/4 × 105 spleen lymphocytes,P ＜ 0.05],and the highest specific CTL that vaccine induced was significantly higher than that of pure antigen (43.3％ versus 31.3％,P ＜ 0.05).Conclusions Humoral and cellular immune response could be effectively stimulated by PVAX1-HPV58mE6E7FcGB composite DNA vaccine.Growth of B16-HPV58E6E7 cells was significantly inhibited in the immunized mice.The cellular immune effect on the vaccine was superior to the pure antigen.Therefore,PVAX1-HPV58mE6E7FcGB could be used as a candidate vaccine for immune therapy to the HPV58 positive tumors and precancerous lesions.

Construction of an anti-tumor immunogene vaccine pVAX-IL-12-GB and its expression in vivo and in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To construct a novel immunogene therapeutic plasmid that expresses human interleukin-12 (IL-12), granulocyte-macrophage colony stimulating factor (GM-CSF) and B7.1 and observe its expression in vivo and in vitro.</p><p><b>METHODS</b>Human IL-12 gene fragment was cloned into the upper stream of IRES gene in the previously constructed plasmid pVAX-IRES-GM-CSF-B7.1, and the positive recombinant plasmid pVAX-IL-12-GB was transfected into 293T cells via Lipofectamine 2000. The expressions of IL-12 and GM-CSF-B7.1 mRNA and proteins in the transfected cells were assayed by RT-PCR and ELISA, and B7.1 expression was tested by fluorescence-activated cell sorting and immunofluorescence assay. The plasmid pVAX-IL-12-GB was delivered into mouse muscle by electroporation, and the expression of IL-12 in the muscle tissue was identified by immunohistochemistry.</p><p><b>RESULTS</b>Enzyme digestion, PCR and sequence analysis all confirmed successful construction of the recombinant plasmid pVAX-IL-12-GB. IL-12, GM-CSF and B7.1 expressions were all detected in transfected 293T cells, and the expression of IL-12 was also detected in the transfected mouse muscular tissues.</p><p><b>CONCLUSION</b>A novel anti-tumor immunogene vaccine constructed can be expressed both in vivo and in vitro, which facilitates further studies of tumor immunogene therapy.</p>

Prokaryotic expression, purification and antigenicity identification of mouse prostate stem cell antigen / 南方医科大学学报

<p><b>OBJECTIVE</b>To amplify mouse prostate stem cell antigen (mPSCA) gene and construct a recombinant plasmid to obtain mPSCA protein and identify its antigenicity.</p><p><b>METHODS</b>The gene of mPSCA was amplified by RT-PCR from mouse prostate cancer cell line RM-1 with the signal peptide sequence removed. The PCR product was cloned into pET-42a prokaryotic expression vector to construct the recombinant plasmid pET-42a-mPSCA, which was transformed into BL21 (DE3) for mPSCA expression. The fusion protein was purified and identified by SDS-PAGE and Western blotting. The antigenicity of the purified protein was characterized by ELISA.</p><p><b>RESULTS</b>The mPSCA gene was obtained with an identical sequence to that retrieved in GenBank. The prokaryotic expression vector for mPSCA was successfully constructed as confirmed by enzyme digestion and DNA sequencing. Both Western blotting and ELISA demonstrated the antigenicity of the purified mPSCA protein.</p><p><b>CONCLUSION</b>The purified mPSCA obtained possesses good antigenicity, which will facilitate further study of immunotherapy for prostate cancer targeting PSCA.</p>

Design and expression of an inhibitor for HIV-1 targeting dendritic cell / 生物工程学报

Human immunodeficiency virus (HIV) infects the host cells by the fusion of viral and cell membranes. Blocking the combining between HIV and the receptors can prevent HIV from entering the host cells. We designed an invasion-inhibitor for HIV-1 targeting dendritic cell (DC), including 2 important HIV-1 receptors CD4 and CCR5, and 2 molecules Flt3-L and Mip-3alpha. With the synthetic gene of the inhibitor, 2 eukaryotic expression vectors pABK-CKR5-CD4/Flt3L-Mip3alpha (pABK-HIV-MF) and pABK-CKR5-CD4 (pABK-HIV-MT) were constructed and transfected into HEK 293 cells for expression. Results from RT-PCR, immunofluorescent assay, ELISA and Western blot approved that the invasion-inhibitor for HIV-1 was successfully and exactly expressed in the eukaryotic cells. Current study formed a solid base for the further research on the function of inhibitors for HIV-1 and elimination targeting DC.

Prokaryotic expression,purification and identification of human prostate stem cell antigen / 解放军医学杂志

Objective To construct the prokaryotic expression plasmid of human prostate stem cell antigen (PSCA),to induce the expression of GST-PSCA fusion protein in E. coli BL21,and to identify the purified recombinant fusion protein. Methods The fragment of PSCA gene was amplified by PCR,and then cloned into the pGEM-T Easy vector. The transitional plasmid Teasy-PSCA was identified by DNA sequencing. The PSCA gene was digested from the plasmid Teasy-PSCA by restrictive enzyme BamH I and Sal I,and then inserted into the pET42a vector which contains a glutathione s-transterase (GST) tag. Following the double restriction enzyme digestion,the recombinant plasmid pET42a-PSCA was obtained and transformed into E. coli BL21 (DE3). The expression of GST-PSCA fusion protein was induced with IPTG. The recombinant fusion protein was purified by passing over a Glutathione Sepharose 4B column,and was identified by SDS-PAGE and Western blotting. Results The length of amplified PSCA gene fragment was consistent with that expected,and the sequence was correct as exemplified by the PSCA gene reported in GenBank. The result of enzyme digestion indicated that the prokaryotic expression plasmid pET42a-PSCA was successfully constructed. After transformation with pET42a-PSCA and induction with IPTG,the recombinant target protein of about 43kD was obtained. The GST-PSCA fusion protein was correctly identified by SDS-PAGE and Western blotting. Conclusions The prokaryotic expression plasmid of human PSCA gene has been successfully constructed. The GST-PSCA fusion protein may express and be purified in E. coli BL21,and it lays a foundation for further study on the anti-prostate cancer gene vaccine.

The Antitumor Effects of Tumor Vaccine with Expression of Granulocyte-Macrophage Colony-Stimulating Factor Anchored on Mouse Melanoma Tumor Cell Surface / 中国肿瘤生物治疗杂志

Objective: To investigate the vaccine potency of GM-CSF anchored B16 tumor cells. Methods: In this study, mGM-CSF was expressed on surface of B16 mice melanoma cells by GPI-modifying. C57BL/6 mice were inoculated with GM-CSF anchored cells and wide-type B16 cells to evaluate whether the GM-CSF anchored cells could elicit a protective and systemtic antitumor response. Results: GM-CSF anchored cells resulted in remarkable loss of tumorgenicity in syngenetic mice. The tumor occurrence rate of GM-CSF anchored B16 cells was 58. 8% on C57BL/6 mice with 1 ? 106 B16 cells/mice inoculated ( n = 12) and that of wide-type B16 cells was 100% , The C57BL/6 mice receiving inoculation with 5 ? 105GM-CSF anchored cells/mice never grew tumor. These mice were challenged with wide-type B16 cells, and only a minority of mice grew tumor after wide-type B16 cells inoculation. Conclusion:GM-CSF protein anchored cells could elicit a protective and systemtic antitumor responses.

Construction of DC-SIGN eukaryotic expression vector and establishment of BHK21 cell line stably transfected by the recombinant vector / 解放军医学杂志

Objective To construct a eukaryotic expressing vector harboring human DC-SIGN, and establish a BHK21 cell line stably and highly expressing DC-SIGN. Methods The DC-SIGN gene fragment which contained Not I and BamH I sites was amplified by PCR from pUNO-hDCSIGN1Aa plasmid, digested with Not I and BamH I, and then cloned into an eukaryotic expression vector pIRES-neo to construct eukaryotic expression vector pIRES-neo-DC-SIGN. The recombined plasmid was identified with Not I and BamH I enzyme digestion and sequencing, the latter was then transfected to BHK21 cells by LipofectamineTM 2000. After screening culture by G418, BHK21 cell line stably expressing DC-SIGN was established. The expression of DC-SIGN was identified by flow cytometry, Western blotting and immunofluorescence method. Results The gene sequence of DC-SIGN was consistent with that of design. PCR and double enzyme digestion analysis showed that the recombinant plasmid pIRES-neo-DC-SIGN was constructed successfully. After transfection, positive clones were selected with G418. After limiting dilution assay, BKH21 cell lines stably expressing DC-SIGN were established. The detection result of flow cytometry showed that the expression ratio of DC-SIGN positive clones was close to 90%. The result of immunofluorescence displayed that the expression of DC-SIGN was mostly located on the surface of cell membrane. Western blotting displayed the specific band of DC-SIGN protein. It showed that the BHK21 cells stably expressing DC-SIGN were successfully established. Conclusion DC-SIGN eukaryotic expression vector has been successfully constructed. The successful establishment of BHK21 cell lines which can stably express DC-SIGN provides a substantial foundation for further study on the DC targeting vaccines.

Construction and expression of human anti-HBs-IFN fusion gene / 解放军医学杂志

Objective To construct eukaryotic expression plasmid pEE14.1-dsFv?pr+,and detect the expression of the recombined gene in eukaryotic CHO-K1 cells.Methods The cationic DNA fragment was cloned into the 3' of VH gene by overlapping extension PCR,and the 6?His tab was inserted to the 3' of VL and human IFN-? gene by the same way.The above mentioned recombinant VH and VL genes were inserted into a pCI-GPI vector first,and then cloned into the pEE14.1 vector to construct the recombinant plasmid pEE14.1-dsFv?pr+.Finally,the recombinant plasmid was transfected into the CHO-K1 cells by LipofectamineTM 2000,and the expression was detected by RT-PCR,ELISA and Western blotting.Results The enzyme digestion and sequencing analysis showed that the recombinant plasmid was successfully constructed.RT-PCR showed that only the cells with transfected plasmid can generate the specific 1700bp fragment.ELISA analysis showed that the production of IFN-?expressed in the supernatant of transfected cells was about 1.1ng/ml.Also,Western blotting could reveal the characteristic band of HBsAg dsFv?pr+ protein.Conclusion The antibody targeting to human IFN-?genes has been successfully expressed in a single open reading frame.Changing the electricity of the antibody may provide the necessary condition for the study of the a new type of anti-HBV drug in nanoscale in the future.