ABSTRACT
In order to achieve large-scale production of HSV-IgM (HSV1, HSV2) human-mouse chimeric antibody in vitro, the gene sequence of the corresponding hybridoma cell was harvested by RNA ligase-mediated rapid amplification of cDNA ends (RLM-RACE) technique to clone the chimeric antibody into eukaryotic expression vectors, and express the target proteins in CHO-S cells. At the same time, the screening process of stable cell lines was optimized, and the pressure conditions of pool construction stage and monoclonal screening stage were explored. Finally, the target protein was purified by protein L affinity purification method and the biological activity was detected. The recombinant IgM antibodies, HSV1 and HSV2, weighted at 899 kDa and 909 kDa respectively, were prepared. The optimal screening pressure was 20P200M (the first phase of pressure) and 50P1000M (the second phase of pressure). The final titer for the monoclonal expression of HSV1-IgM and HSV2-IgM was 1 620 mg/L and 623 mg/L, respectively. This study may facilitate the development of quality control products of HSV1 and HSV2 IgM series recombinant antibodies as well as efficient expression of IgM subtype antibodies in vitro.
Subject(s)
Cricetinae , Humans , Animals , Mice , Immunoglobulin M/genetics , Antibodies, Viral , CHO Cells , Cricetulus , Hybridomas , Recombinant Fusion ProteinsABSTRACT
Microglia play multiple roles in such processes as brain development, homeostasis, and pathology. Due to their diverse mechanisms of functions, the complex sub-classifications, and the large differences between different species, especially compared with humans, very different or even opposite conclusions can be drawn from studies with different research models. The choice of appropriate research models and the associated tools are thus key ingredients of studies on microglia. Mice are the most commonly used animal models. In this review, we summarize in vitro and in vivo models of mouse and human-derived microglial research models, including microglial cell lines, primary microglia, induced microglia-like cells, transgenic mice, human-mouse chimeric models, and microglial replacement models. We also summarize recent developments in novel single-cell and in vivo imaging technologies. We hope our review can serve as an efficient reference for the future study of microglia.
ABSTRACT
In order to prepare human-mouse chimeric cytomegalovirus-immunoglobulin M (CMV-IgM) in vitro and study the effects of different signal peptides on the secretion of CMV-IgM, genes were amplified from hybridoma cell line using RLM-RACE to construct the expression vector of chimeric CMV-IgM. Then, the signal peptide of SigF itself was replaced by five different secreted signal peptides (SigA-SigE) by PCR method, and the CHO cell was chosen as host cell for in vitro expression. SDS-PAGE, SEC-HPLC and ELISA experiments were carried out to evaluate the protein expression level and immunoreactivity of the purified CMV-IgM. A 910 kDa recombinant protein was successfully prepared and signal peptides (SigA-SigE) had an increased expressed CMV-IgM, which were 6.72, 5.19, 1.44, 1.85 and 1.98 times higher than that of the CMV 6# cell signal peptide SigF. In summary, this work provides a theoretical basis for the development of human-mouse chimeric CMV-IgM, and a novel route to increase the expression level of CMV-IgM.
Subject(s)
Animals , Cricetinae , Humans , Mice , Antibodies, Viral , Genetics , Allergy and Immunology , Cytomegalovirus , Allergy and Immunology , Enzyme-Linked Immunosorbent Assay , Gene Expression , Immunoglobulin M , Allergy and Immunology , Protein Sorting Signals , Recombinant Fusion Proteins , Allergy and ImmunologyABSTRACT
Objective:On the basis of the use of chemical methods to establish mouse model of lupus nephritis and its biological identification , we investigate the reverse effect of pathological lesions of B 7-1 human-mouse chimeric antibody blockade against B7/D28 signaling pathway in mice with lupus nephritis model.Methods:Pristane was injected intraperitoneally to 6-week-old female C57BL/6J mice at dose of 0.5 ml per mouse in one go,and urine protein,ANA and renal pathological changes were detected on a monthly basis.Mice whose urine protein content reached ++and ANA fluorescence intensity reached ++were randomly devided into three groups ,five each.Antibody intervention group was sequentially injected with B 7-1-mouse chimeric antibody by orbital venous , positive control group was injected with immunosuppressant CTX , negative control group was injected with isotype control IgG.Urine protein and ANA were also detected on a monthly basis.Mice were sacrificed three months after intervention was executed.Kidney was used for H&E dying , IC detection and electric microscope observation.Results: After four-month Pristane induction , urine protein content of 80%mice reached +-+++,meanwhile,serum ANA fluorescence intensity reached ++-+++.Glomerulonephritis infiltrating cells were observed Mice with urine protein and ANA , glomerular inflammatory cell infiltration , tubular epithelial cell degeneration visible edema ,vascular congestion significantly ,fibrosis.After antibody intervention ,urine protein content in antibody intervention group gradually reduced from ++-+++to ±-+++,ANA ++-+++to +-++,and were significantly different from that in the negative control group ( P<0.01 ).Analysis of kidney H&E dying showed that antibody glomerular infiltration of inflammatory cells in the intervention group and tubular congestion and other symptoms were improved significantly.Immunofluorescence staining indicated that fluorescence intensity of IC was significantly reduced in the antibody intervention group.Electron dense deposits reduction and glomerular basement membrane uniformity were observed in antibody intervention group by electric microscope when compared with the negative control group.Conclusion:B7-1 antibodies could downregulate immune response through inhibiting B 7-1/CD28 signaling pathway , reducing the production of autoantibodies and reversing pathological damage caused by autoimmune response .
ABSTRACT
Objective To express human-mouse chimeric antibody against anthrax protective anti-gen and to analyze its biological activities. Methods A new mammalian bipromoter expression vector was constructed with dihydrofolate reduetase(DHFR) gene as the selection and complication marker. First, the light and heavy chain variable region gene of the monoclonal antibody 5E1 were cloned by RT-PCR, at the same time the human IgG1 heavy chain constant region gene and kappa type constant region gene were cloned. Next, the human-mouse chimeric antibody genes were synthesized by fusion PCR. Then, the hu-man-mouse chimeric antibody gene were inserted into MCS of pSecTag and B1 to construct pSecTag-5E1L and B1-5E1H, respectively. Finally, heavy chain expression cassette excised from the B1-5E1H with Bgl Ⅱ/BamH Ⅰ was further cloned into the Bgl Ⅱ site of the pSecTag-5E1L to construct pSecTag-5E1. Plasmid pSecTag-5E1 was transfected into CHO(dhfr) engineering cells and high production cell clones that were screened by enhancing MTX concentration. After collecting medium and purifying chimeric antibody with af-finity chromatogram, purified chimeric antibody was analyzed by SDS-PAGE, Western blot. Results A sta-ble and high production cell line was acquired at MTX concentration 5×10~(-8) mol/L. Conclusion The hu-man-mouse chimeric antibodies were successfully expressed in CHO cells.
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In order to reduce its immunogenicity and increase its therapeutic usefullness, the murine anti-gastric cancer McAb 3H11 was genetically engineered into a human-mouse chimeric antibody. The 3H11 light and heavy chain variable genes were inserted into chimeric antibody expression vectors respectively. The chimeric light chain expression vector was first transfected into murine Sp2/0 myeloma cells using lipofectin. Transfectants that stably expressed human-mouse chimeric light chain were isolated by mycophenolic acid selection. Then the chimeric heavy chain expression vector was transfected into the transfectomas. Histidinol resistent cells were obtained and among these, clones stably secreting human-mouse chimeric antibodies were selected. The expression of human-mouse chimeric light and heavy chain mRNAs were proved by RT-PCR and the expressed chimeric antibody was demonstrated capable of binding to human gastric cancer cell MGC803