Reactive oxygen species（ROS） plays a key role in human heart diseases. Glutathione peroxidase（GPX） functions as an antioxidant as it catalyzes the reduction of hydroperoxide. In order to investigate the antioxidan...Reactive oxygen species（ROS） plays a key role in human heart diseases. Glutathione peroxidase（GPX） functions as an antioxidant as it catalyzes the reduction of hydroperoxide. In order to investigate the antioxidant effect of human selenium-containing single-chain Fv（Se-scFv-B3）, a new mimic of GPX, a model system of hydrogen peroxide（H202）-induced rat cardiac myocyte damage was established. The cardiac myocyte damage was characte- rized in terms of cell viability, lipid peroxidation, cell membrane integrity, and intracellular H202 level. The Se-scFv-B3 significantly reduced H2O2-induced cell damage as shown by the increase of cell viability, the decline of malondialdehyde（MDA） production, lactate dehydrogenase（LDH） release, and intracellular H2O2 level. So Se-scFv-B3 may have a great potential in the treatment of human heart diseases induced by ROS.展开更多
Summary: A three-dimensional (3D) graphic model of a single-chain Fv (scFv) which was derived from an anti-human placental acidic isoferritin (PAF) monoclonal antibody (MAb) was construct- ed by a homologous protein...Summary: A three-dimensional (3D) graphic model of a single-chain Fv (scFv) which was derived from an anti-human placental acidic isoferritin (PAF) monoclonal antibody (MAb) was construct- ed by a homologous protein-predicting computer algorithm on Silicon graphic computer station. The structure, surface static electricity and hydrophobicity of scFv were investigated. Computer graphic modelling indicated that all regions of scFv including the linker, variable regions of the heavy (VH) and light (VL) chains were suitable. The VH region and the VL region were involved in composing the 'hydrophobic pocket'. The linker was drifted away VH and VL regions. The complementarity determining regions (CDRs) of VH and VL regions surrounded the 'hydrophobic pocket'. This study provides a theory basis for improving antibody affinity, investigating antibody structure and analyzing the functions of VH and VL regions in antibody activity.展开更多
AIM: To construct fusion protein of a single-chain antibody (scFv) against transferrin receptor (TfR) with alkaline phosphatase(AP). METHODS: The VH-linker-VL,namely scFv gene,was prepared by amplifying the VH and VL ...AIM: To construct fusion protein of a single-chain antibody (scFv) against transferrin receptor (TfR) with alkaline phosphatase(AP). METHODS: The VH-linker-VL,namely scFv gene,was prepared by amplifying the VH and VL genes from plasmid pGEM-T-VH and pGEM-T-VL with splicing overlap extension polymerase chain reaction (SOE PCR). After the ScFv gene was modified by 5/71 and Not I,it was subcloned into the secretory expression vector pUC19/119, and then was transformed into E.coli TG1.The positive colonies were screened by colony PCR and their expressions were induced by IPTG.ScFv gene was gained by digesting ScFv expression vector pUC19/119 with 5/71 and NotI restriction enzymes, then subcloned into expression vector pDAP2, followed by transformation in E.coli TG1.The positive colonies were selected by bacterial colony PCR.The expression of fusion protein (scFv-AP) was induced by IPTG.Its activity was detected by enzyme immunoassay. The molecular weights of scFv and scFv-AP were measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). RESULTS: The product of SOE PCR formed a band of 700 bp in agarose gel electrophoresis. SDS-PAGE demonstrated the molecular weight of scFv was 27 ku.Immunofluorescent assay (IFA) demonstrated its reactivity with TfR.The molecular weight of scFv-AP was 75 ku.Enzyme immunoassay showed that scFv-AP could specifically bind to human TfR and play AP activity. CONCLUSION: We have successfully prepared the anti-human TfR scFv and constructed the fusion protein of scFv and AP.It is promising for immunological experiments.展开更多
Objective: To Obtain purified genetic eogineering recombinant scFv-fusion protein with potentialities of clinical application. Methods: Mouse anti-hepatocellular carcinoma (HCC) single chain Fv fragment (mscFv25 ) was...Objective: To Obtain purified genetic eogineering recombinant scFv-fusion protein with potentialities of clinical application. Methods: Mouse anti-hepatocellular carcinoma (HCC) single chain Fv fragment (mscFv25 ) was fused to human TNFa gene, then mscFv25-TNFa was subcloned into prokaryotic GST fusion expression vector pGEX 4T-l, and ex-. pressed in the host E. colt induced by IPTG. Expressed proteins as inclusion bodies were solubilized, solubilized and purified by GST affinity chromatography. The cytotoxity of mscFv25-TNFa was evaluated on SMMC-7721 by MTT, and the targeting therapeutic value was revealed in nude mice bearing HCC xenografts. Results: The specificity and affinity of mscFv25-TNFa were not markedly reduced compared with its parental antibody HAb25 against SMMC-7721 antigen. In vitro target cell SMMC-7721 was insensitive to mscFv25-TNFa. In the mscFv25-TNFa had certain targeting cytotoxicity and caused complete tumor disappearance in 4 of 14 mice, and the side effects of TNFa were much weaker in mscFv25-TNFa group than in group. Conclusion: SMMC-7721 may belong to the TNF-resistant type. While in the trial, mscFv25-TNFa caused complete tumor disappearance in 4 of 14 mice, but no disappearance in TNFa group, suggesting that mscFv25-TNFa had certain tar geting cytotoxicity, and the cytotoxicity of TNFa depended on some other factors in the. It may damage vascular endothelial cell and lead to ischemic necrosis, or induce the tumor cell to apoptosis and some agents to play the the of actinmycin-D in vivo. The targeting of mscFv25 can diminish unspecific cytotoxicity of TNFa, thus attenuate the side effects of TNFa.展开更多
Glutathione peroxidase（GPX） plays an important role in scavenging reactive oxygen species. A series of catalytic antibodies with GPX activity have been generated by the authors of＇ this study. To obtain humanized c...Glutathione peroxidase（GPX） plays an important role in scavenging reactive oxygen species. A series of catalytic antibodies with GPX activity have been generated by the authors of＇ this study. To obtain humanized catalytic antibodies, the phage-displayed human antibody library was used to select novel antibodies by repetitive screening, Phage antibodies, scFv-B8 and scFv-H6 with the GSH-binding site, were obtained from the library by enzyme-linked immu- nosorbent assay（ELISA） analysis with 4 rounds of scelection against their respective haptens, S-2,4-dinitriphenyl t-butyl ester（GStI-s-DNP-Bu） and S-2,4-dinit,-iphenyl t-hexyl ester（GSH-s-I）NP-He）. Nevertheless, several studies need to be condueted to determine whether scFv-B8 and seFv-tI6 possess GPX activity. 1＇o enhance the speed of the selection, selenocysteine（Sec, the catalytic group of GPX） was incorporated directly into the phages, scFv-B8 and seFv-H6, by chemical mutation to form the phages Se-scFv-B8 and Se-scFv-H6. The GPX activities were found to be 3012 units/μmol and 2102 units/μmol, respectively. To improve the GPX activity of the phage Se-scFv-B8, DNA shuffling was used to construct a secondary library and another positive phage antibody scFv-B9 was screened out by another panning against GSH-s-DNP-Bu. When Sec was incorporated via chemical mutation into the phage antibody scFv-B9, its GPX activity reached 3560 units/μmol, which is 1.17-fold higher than the phage antibody Se-scFv-B8 and almost approached the order of magnitude of native GPX. The rapid selection is the prerequisite for generating humanized Se-seFv with GPX activity.展开更多
Amyloid-beta peptides （Aβ） are believed to be .responsible for the mental decline in patients with Alzheimer＇s reported that pathology in vaccination disease （AD）. In 1999, Schenk et all immunization with Aβ at...Amyloid-beta peptides （Aβ） are believed to be .responsible for the mental decline in patients with Alzheimer＇s reported that pathology in vaccination disease （AD）. In 1999, Schenk et all immunization with Aβ attenuated AD-like the PDAPP mouse, and developed a new approach to AD. Such vaccines were successfully tested in mouse models of AD for the reduction of Aβ plaque burden and the improvement of cognitive performance. However, 6% of AD patients developed symptoms of brain inflammation after vaccination that resembled enceohalitis or meningitis.展开更多
基金Supported by the Grants from Department of Science and Technology of Jilin Province, China(No.20070726)Bureau of Science and Technology of Changchun City, China(No.2005038).
文摘Reactive oxygen species（ROS） plays a key role in human heart diseases. Glutathione peroxidase（GPX） functions as an antioxidant as it catalyzes the reduction of hydroperoxide. In order to investigate the antioxidant effect of human selenium-containing single-chain Fv（Se-scFv-B3）, a new mimic of GPX, a model system of hydrogen peroxide（H202）-induced rat cardiac myocyte damage was established. The cardiac myocyte damage was characte- rized in terms of cell viability, lipid peroxidation, cell membrane integrity, and intracellular H202 level. The Se-scFv-B3 significantly reduced H2O2-induced cell damage as shown by the increase of cell viability, the decline of malondialdehyde（MDA） production, lactate dehydrogenase（LDH） release, and intracellular H2O2 level. So Se-scFv-B3 may have a great potential in the treatment of human heart diseases induced by ROS.
文摘Summary: A three-dimensional (3D) graphic model of a single-chain Fv (scFv) which was derived from an anti-human placental acidic isoferritin (PAF) monoclonal antibody (MAb) was construct- ed by a homologous protein-predicting computer algorithm on Silicon graphic computer station. The structure, surface static electricity and hydrophobicity of scFv were investigated. Computer graphic modelling indicated that all regions of scFv including the linker, variable regions of the heavy (VH) and light (VL) chains were suitable. The VH region and the VL region were involved in composing the 'hydrophobic pocket'. The linker was drifted away VH and VL regions. The complementarity determining regions (CDRs) of VH and VL regions surrounded the 'hydrophobic pocket'. This study provides a theory basis for improving antibody affinity, investigating antibody structure and analyzing the functions of VH and VL regions in antibody activity.
基金Supported by Natural Key and Basic Research Development Program,No.2002CB513109
文摘AIM: To construct fusion protein of a single-chain antibody (scFv) against transferrin receptor (TfR) with alkaline phosphatase(AP). METHODS: The VH-linker-VL,namely scFv gene,was prepared by amplifying the VH and VL genes from plasmid pGEM-T-VH and pGEM-T-VL with splicing overlap extension polymerase chain reaction (SOE PCR). After the ScFv gene was modified by 5/71 and Not I,it was subcloned into the secretory expression vector pUC19/119, and then was transformed into E.coli TG1.The positive colonies were screened by colony PCR and their expressions were induced by IPTG.ScFv gene was gained by digesting ScFv expression vector pUC19/119 with 5/71 and NotI restriction enzymes, then subcloned into expression vector pDAP2, followed by transformation in E.coli TG1.The positive colonies were selected by bacterial colony PCR.The expression of fusion protein (scFv-AP) was induced by IPTG.Its activity was detected by enzyme immunoassay. The molecular weights of scFv and scFv-AP were measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). RESULTS: The product of SOE PCR formed a band of 700 bp in agarose gel electrophoresis. SDS-PAGE demonstrated the molecular weight of scFv was 27 ku.Immunofluorescent assay (IFA) demonstrated its reactivity with TfR.The molecular weight of scFv-AP was 75 ku.Enzyme immunoassay showed that scFv-AP could specifically bind to human TfR and play AP activity. CONCLUSION: We have successfully prepared the anti-human TfR scFv and constructed the fusion protein of scFv and AP.It is promising for immunological experiments.
文摘Objective: To Obtain purified genetic eogineering recombinant scFv-fusion protein with potentialities of clinical application. Methods: Mouse anti-hepatocellular carcinoma (HCC) single chain Fv fragment (mscFv25 ) was fused to human TNFa gene, then mscFv25-TNFa was subcloned into prokaryotic GST fusion expression vector pGEX 4T-l, and ex-. pressed in the host E. colt induced by IPTG. Expressed proteins as inclusion bodies were solubilized, solubilized and purified by GST affinity chromatography. The cytotoxity of mscFv25-TNFa was evaluated on SMMC-7721 by MTT, and the targeting therapeutic value was revealed in nude mice bearing HCC xenografts. Results: The specificity and affinity of mscFv25-TNFa were not markedly reduced compared with its parental antibody HAb25 against SMMC-7721 antigen. In vitro target cell SMMC-7721 was insensitive to mscFv25-TNFa. In the mscFv25-TNFa had certain targeting cytotoxicity and caused complete tumor disappearance in 4 of 14 mice, and the side effects of TNFa were much weaker in mscFv25-TNFa group than in group. Conclusion: SMMC-7721 may belong to the TNF-resistant type. While in the trial, mscFv25-TNFa caused complete tumor disappearance in 4 of 14 mice, but no disappearance in TNFa group, suggesting that mscFv25-TNFa had certain tar geting cytotoxicity, and the cytotoxicity of TNFa depended on some other factors in the. It may damage vascular endothelial cell and lead to ischemic necrosis, or induce the tumor cell to apoptosis and some agents to play the the of actinmycin-D in vivo. The targeting of mscFv25 can diminish unspecific cytotoxicity of TNFa, thus attenuate the side effects of TNFa.
基金Supported by the National Natural Science Foundation of China(Nos 20072010 and 20572035) and the Science Foundation ofJilin University(Nos419070100087 and 01208006)
文摘Glutathione peroxidase（GPX） plays an important role in scavenging reactive oxygen species. A series of catalytic antibodies with GPX activity have been generated by the authors of＇ this study. To obtain humanized catalytic antibodies, the phage-displayed human antibody library was used to select novel antibodies by repetitive screening, Phage antibodies, scFv-B8 and scFv-H6 with the GSH-binding site, were obtained from the library by enzyme-linked immu- nosorbent assay（ELISA） analysis with 4 rounds of scelection against their respective haptens, S-2,4-dinitriphenyl t-butyl ester（GStI-s-DNP-Bu） and S-2,4-dinit,-iphenyl t-hexyl ester（GSH-s-I）NP-He）. Nevertheless, several studies need to be condueted to determine whether scFv-B8 and seFv-tI6 possess GPX activity. 1＇o enhance the speed of the selection, selenocysteine（Sec, the catalytic group of GPX） was incorporated directly into the phages, scFv-B8 and seFv-H6, by chemical mutation to form the phages Se-scFv-B8 and Se-scFv-H6. The GPX activities were found to be 3012 units/μmol and 2102 units/μmol, respectively. To improve the GPX activity of the phage Se-scFv-B8, DNA shuffling was used to construct a secondary library and another positive phage antibody scFv-B9 was screened out by another panning against GSH-s-DNP-Bu. When Sec was incorporated via chemical mutation into the phage antibody scFv-B9, its GPX activity reached 3560 units/μmol, which is 1.17-fold higher than the phage antibody Se-scFv-B8 and almost approached the order of magnitude of native GPX. The rapid selection is the prerequisite for generating humanized Se-seFv with GPX activity.
基金the grants from National Natural Science Foundation of China (No. 3040052)Natural Science and Technology Foundation of Guangdong Province (No. 04300218, 2005B10401047, 2006B36004001)Foundation of Science and Technology Bureau of Guangzhou City (No. 2004Z3-E0151, 2005Z3-E4021, 2006J1-C0101)
文摘Amyloid-beta peptides （Aβ） are believed to be .responsible for the mental decline in patients with Alzheimer＇s reported that pathology in vaccination disease （AD）. In 1999, Schenk et all immunization with Aβ attenuated AD-like the PDAPP mouse, and developed a new approach to AD. Such vaccines were successfully tested in mouse models of AD for the reduction of Aβ plaque burden and the improvement of cognitive performance. However, 6% of AD patients developed symptoms of brain inflammation after vaccination that resembled enceohalitis or meningitis.
