The present study aimed at the preparation of monoclonal antibody against the recombinant PthA-NLS and the isolation of the relative ScFv （single chain variable fragment） genes, providing the possibility to better u...The present study aimed at the preparation of monoclonal antibody against the recombinant PthA-NLS and the isolation of the relative ScFv （single chain variable fragment） genes, providing the possibility to better understand the pathogenesis mechanism via PthA, and developing proper construct for future experimentation to obtain citrus plants resistant to canker disease by transformation and plant antibody techniques. The recombinant polypeptide PthA-NLS was injected into Balb/c mice to produce monoclonal antibody. Total RNA was isolated from the hybridoma cell line 3D10H2 which secreted anti- PthA-NLS McAb, and the variable region genes were amplified with specific primers by RT-PCR and SOE-PCR （splicing by overlap extension）, and then the ScFv gene was isolated. The recombinant ScFv gene was cloned into pGEM-T and pET32a（＋） vector. The later plasmid was transferred into E. coli BL21 （DE3） and the expression of the recombinant protein was induced. Three cell lines producing monoclonal antibody against PthA-NLS were acquired and named 1C8H1, 2D12B6, and 3D8A10. The recombinant ScFv gene of about 750 bp was constructed. The sequencing results showed that the ScFv gene consists of a 360 bp heavy chain, a 342 bp light chain, and a 45 bp linker region. The recombinant fusion ScFv protein was expressed by IPTG induction, and a 44.5 kDa of recombinant fusion protein was obtained. In conclusion, we obtained three cell lines stably producing monoclonal antibody specifically bound to PthA-NLS, and the relative ScFv gene was constructed and successfully expressed in E. coli. These results may play an important role in further understanding the pathogenesis mechanism and in the development of possible citrus resistant to canker disease by genetic transformation and plant antibiobody.展开更多
Objective To design and construct the eukaryotic expression vector which expresses Anti-CD3 ScFv-B7.1 fusion molecules and predict the biological characteristics, the rationality and feasibility of the spacer. Methods...Objective To design and construct the eukaryotic expression vector which expresses Anti-CD3 ScFv-B7.1 fusion molecules and predict the biological characteristics, the rationality and feasibility of the spacer. Methods To analyze the flexibility, Hoop & Woods hydrophilicity and the epitope of Anti-CD3 ScFv-B7.1 fusion molecule at secondary structure level by computer simulation utilizing the GoldKey software. Results By comparing with Anti-CD3 ScFv and B7.1 respectively, it shows that Anti-CD3 ScFv-B7.1 fusion molecules can form correct secondary structure with the linking of the spacer, the fusion does not change the original hydrophilicity and epitopes of both Anti-CD3 ScFv and B7.1, no new epitopes emerge; The spacer is flexible and shows low antigenicity. Conclusion The design of Anti-CD3 ScFv-B7.1 fusion molecule are rational and feasible, the expressed fusion protein could retain the maximum biological activity and the function of both Anti-CD3 ScFv and B7.1.展开更多
To obtain single chain variable fragment （scFv） and bivalent single chain variable fragment （bsFv） against transferrin receptor, up-stream and down-stream primers were designed according to the complementary seque...To obtain single chain variable fragment （scFv） and bivalent single chain variable fragment （bsFv） against transferrin receptor, up-stream and down-stream primers were designed according to the complementary sequences of FR1 region of variable heavy （VH） and FR4 of variable light （VL）, respectively, which contained inter-linker G4S and the restriction endonuclease SfiI, AscI and NotI. Two pieces of scFv fragments were first amplified through PCR and then inserted into plasmid pAB1, which could express scFv protein once induced by IPTG in the host bacteria. To express scFv and bsFv, E. coli TG1 was cultured in LB broth and was induced by IPTG. The restriction enzyme digestion map and DNA sequencing demonstrated that scFv and bsFv genes were successfully inserted into the expression plasmid. SDS-PAGE and Western blotting revealed the protein band at 35kD and 60kD, which were consistent with the molecular weight of scFv and bsFv respectively. Flow cytometry showed that scFv and bsFv harbored the specific binding activity with TfR expressed in various tumor cells, and the avidity of bsFv was higher than that of the parent scFv.展开更多
基金supported by the Scientific and Technical Project of Hunan Province,China(04NK1005)
文摘The present study aimed at the preparation of monoclonal antibody against the recombinant PthA-NLS and the isolation of the relative ScFv （single chain variable fragment） genes, providing the possibility to better understand the pathogenesis mechanism via PthA, and developing proper construct for future experimentation to obtain citrus plants resistant to canker disease by transformation and plant antibody techniques. The recombinant polypeptide PthA-NLS was injected into Balb/c mice to produce monoclonal antibody. Total RNA was isolated from the hybridoma cell line 3D10H2 which secreted anti- PthA-NLS McAb, and the variable region genes were amplified with specific primers by RT-PCR and SOE-PCR （splicing by overlap extension）, and then the ScFv gene was isolated. The recombinant ScFv gene was cloned into pGEM-T and pET32a（＋） vector. The later plasmid was transferred into E. coli BL21 （DE3） and the expression of the recombinant protein was induced. Three cell lines producing monoclonal antibody against PthA-NLS were acquired and named 1C8H1, 2D12B6, and 3D8A10. The recombinant ScFv gene of about 750 bp was constructed. The sequencing results showed that the ScFv gene consists of a 360 bp heavy chain, a 342 bp light chain, and a 45 bp linker region. The recombinant fusion ScFv protein was expressed by IPTG induction, and a 44.5 kDa of recombinant fusion protein was obtained. In conclusion, we obtained three cell lines stably producing monoclonal antibody specifically bound to PthA-NLS, and the relative ScFv gene was constructed and successfully expressed in E. coli. These results may play an important role in further understanding the pathogenesis mechanism and in the development of possible citrus resistant to canker disease by genetic transformation and plant antibiobody.
文摘Objective To design and construct the eukaryotic expression vector which expresses Anti-CD3 ScFv-B7.1 fusion molecules and predict the biological characteristics, the rationality and feasibility of the spacer. Methods To analyze the flexibility, Hoop & Woods hydrophilicity and the epitope of Anti-CD3 ScFv-B7.1 fusion molecule at secondary structure level by computer simulation utilizing the GoldKey software. Results By comparing with Anti-CD3 ScFv and B7.1 respectively, it shows that Anti-CD3 ScFv-B7.1 fusion molecules can form correct secondary structure with the linking of the spacer, the fusion does not change the original hydrophilicity and epitopes of both Anti-CD3 ScFv and B7.1, no new epitopes emerge; The spacer is flexible and shows low antigenicity. Conclusion The design of Anti-CD3 ScFv-B7.1 fusion molecule are rational and feasible, the expressed fusion protein could retain the maximum biological activity and the function of both Anti-CD3 ScFv and B7.1.
基金supported by a grant from "863" program of China (No. 2006AA02Z158)the Ministry of Education Science Foundation of China (No. 20060487024)Science and Technology project of Jiangxi Province Education Department (No. 2006-86).
文摘To obtain single chain variable fragment （scFv） and bivalent single chain variable fragment （bsFv） against transferrin receptor, up-stream and down-stream primers were designed according to the complementary sequences of FR1 region of variable heavy （VH） and FR4 of variable light （VL）, respectively, which contained inter-linker G4S and the restriction endonuclease SfiI, AscI and NotI. Two pieces of scFv fragments were first amplified through PCR and then inserted into plasmid pAB1, which could express scFv protein once induced by IPTG in the host bacteria. To express scFv and bsFv, E. coli TG1 was cultured in LB broth and was induced by IPTG. The restriction enzyme digestion map and DNA sequencing demonstrated that scFv and bsFv genes were successfully inserted into the expression plasmid. SDS-PAGE and Western blotting revealed the protein band at 35kD and 60kD, which were consistent with the molecular weight of scFv and bsFv respectively. Flow cytometry showed that scFv and bsFv harbored the specific binding activity with TfR expressed in various tumor cells, and the avidity of bsFv was higher than that of the parent scFv.
