[ Objective] To prepare the monoclonal antibody against chicken major histocompatibility complex class II molecules （MHC II）. [ Method ] The prokaryotic expression of the gene fragments of exons 2 -6 encoding alpha ...[ Objective] To prepare the monoclonal antibody against chicken major histocompatibility complex class II molecules （MHC II）. [ Method ] The prokaryotic expression of the gene fragments of exons 2 -6 encoding alpha chain of MHC II and exons 3 -6 encoding beta chain of MHC II were performed based on its protein sequences. After BALB/c mice were immunized with the purified fusion proteins, the mouse spleen cells were fused with mouse myeloma cells SP2/0. Then the positive hybridoma cells were screened and detected by indirect enzyme-linked immunosorbent assay （ELISA）. [ Result] One hybridoma cell strain secreting monoclonal antibody against alpha chain and two strains secreting monoclonal antibody against beta chain were obtained. These three hybridoma cell strains were named as MHC II alpha-4, MHC II betas-2 and MCH II betas-31, respectively. Their titers of ascites in indirect ELISA were 1 ： 256 000, 1 ： 256 000 and 1 ： 1 280 000, respectively. These antibodies could specifically recog- nize MHC II alpha chain or beta chain in western blotting. [ Conclusion] Three obtained hybridoma stains can stably produce the monoclonal antibody against chicken MHC class II molecules.展开更多
DNA fragments encoding the light chain and heavy chain genes of an anti-human HER II antibody, trastuzumab, fused with an egg-lysozyme signal peptide were synthesized based on the codon bias of the methylotrophic yeas...DNA fragments encoding the light chain and heavy chain genes of an anti-human HER II antibody, trastuzumab, fused with an egg-lysozyme signal peptide were synthesized based on the codon bias of the methylotrophic yeast Pichia pastoris. These fragments were inserted into a site between the AOX 1-promoter and -terminator in pPICZ A to be expressed by P. pastoris. The expression vector was linearized, and introduced into P. pastoris GS115 by electroporation. After the checking of several transformants with PCR to ensure a precise insertion, one was selected and cultured to examine antibody production. The level of production reached 10 mg/L in a flask with medium containing 1% methanol. The heavy chain and light chain of the product were assembled to form a hetero tetramer, as detected by dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). N-terminal amino acid sequencing revealed that the signal peptides of both chains were well processed. The mobility of the product in SDS-PAGE after treatment with Peptide N-Glycosidase F indicated the heavy chain to be N-glycosylated. Further analysis of the N-glycans with a mass spectrometer revealed a mixture of Man9-GlcNAc2, Man10-GlcNAc2, Man11-GlcNAc2 and Man12-GlcNAc2, but no hyper-mannosylated glycans. ELISA, surface plasmon resonance, and flow cytometric studies showed the affinity curve and Kd value for the antigen, HER II, and reactivity to a HER2-overexpressing breast cancer cell-line, SK-BR-3, to be almost the same as for the clinically used trastuzumab produced by CHO.展开更多
基金supported by the National Natural Science Foundation (30671537)
文摘[ Objective] To prepare the monoclonal antibody against chicken major histocompatibility complex class II molecules （MHC II）. [ Method ] The prokaryotic expression of the gene fragments of exons 2 -6 encoding alpha chain of MHC II and exons 3 -6 encoding beta chain of MHC II were performed based on its protein sequences. After BALB/c mice were immunized with the purified fusion proteins, the mouse spleen cells were fused with mouse myeloma cells SP2/0. Then the positive hybridoma cells were screened and detected by indirect enzyme-linked immunosorbent assay （ELISA）. [ Result] One hybridoma cell strain secreting monoclonal antibody against alpha chain and two strains secreting monoclonal antibody against beta chain were obtained. These three hybridoma cell strains were named as MHC II alpha-4, MHC II betas-2 and MCH II betas-31, respectively. Their titers of ascites in indirect ELISA were 1 ： 256 000, 1 ： 256 000 and 1 ： 1 280 000, respectively. These antibodies could specifically recog- nize MHC II alpha chain or beta chain in western blotting. [ Conclusion] Three obtained hybridoma stains can stably produce the monoclonal antibody against chicken MHC class II molecules.
文摘DNA fragments encoding the light chain and heavy chain genes of an anti-human HER II antibody, trastuzumab, fused with an egg-lysozyme signal peptide were synthesized based on the codon bias of the methylotrophic yeast Pichia pastoris. These fragments were inserted into a site between the AOX 1-promoter and -terminator in pPICZ A to be expressed by P. pastoris. The expression vector was linearized, and introduced into P. pastoris GS115 by electroporation. After the checking of several transformants with PCR to ensure a precise insertion, one was selected and cultured to examine antibody production. The level of production reached 10 mg/L in a flask with medium containing 1% methanol. The heavy chain and light chain of the product were assembled to form a hetero tetramer, as detected by dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). N-terminal amino acid sequencing revealed that the signal peptides of both chains were well processed. The mobility of the product in SDS-PAGE after treatment with Peptide N-Glycosidase F indicated the heavy chain to be N-glycosylated. Further analysis of the N-glycans with a mass spectrometer revealed a mixture of Man9-GlcNAc2, Man10-GlcNAc2, Man11-GlcNAc2 and Man12-GlcNAc2, but no hyper-mannosylated glycans. ELISA, surface plasmon resonance, and flow cytometric studies showed the affinity curve and Kd value for the antigen, HER II, and reactivity to a HER2-overexpressing breast cancer cell-line, SK-BR-3, to be almost the same as for the clinically used trastuzumab produced by CHO.
