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AIM: To amplify from leader peptide region an d obtain human monoclonal anti-D variable region gene with high specificity and affinity, and analyze the nucleotide and deduced amino acid sequences.ME THODS: The total RNA was extracted from an Epstein-Barr-virus-transforme d cell line secreting monoclonal anti- (rhesus D) antibody. The leader region pri mers containing a ribosome recognition site were designed. By using PCR method, the cDNA of human anti-(rhesus D) antibody (IgM ?) variable region gene was amp lified. Cloning and subsequent sequence analysis of the variable region gene was performed. The deduced amino acid sequence was also compared and analyzed with previ ously published sequences.RESULTS: A band of approximate 440 and 410 base pairs were amplified using heavy chain primers and light chain primer s, respectively. Sequence analysis indicated that the deduced amino acid sequenc e w as in agreement with the characterization of the amino acid present in the human Ig variable region. CONCLUSION: The cloning and sequencing of a human anti- (Rhesus D) antibody variable region cDNA will make benefits for pro duction of recombinant anti-(Rhesus D) antibody and prevention of Rh haemolytic disease in newborns.
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AIM:To obtain the light chain region(VL) and heavy chain region(VH) genes from the hybridoma cell line and analyse their sequence for construction of the engineering antibody against hCD154. METHODS: In this research ,total RNA was extracted from the hybridoma cell line 7E8, which secretes McAb against hCD154, and subjected to reverse transcription. The VL gene and VH gene were amplified by PCR, cloned into puc18 vector and sequenced by Sanger's dideoxymediated chain-termination method. RESULTS: The VL cDNA of 7E8 McAb consists of 341 bp encoding 113 amino acid residues. Compared with mouse Ig database, the VL region is in accord with the characterization of DNA sequence present in the mouse Ig Vk region , it belong to mouse V?2 light chain. The VH cDNA of 7E8 McAb consists of 354 bp encoding 118 amino acid residues. Compared with mouse Ig database, the VH region is in accord with the characterization of DNA sequence present in the mouse Ig VH region. CONCLUSION: The DNA squence analysis showed that the cloned genes code the light and heavy chain variable region of mouse respectively.
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We produced two murine monoclonal antibodies designated S2E1 and S2C11, which recognize S antigen of hepatitis B virus (HBsAg). S2E1 could bind to denatured form of recombinant HBsAg as well as native form of HBsAg, but S2C11 could bind only to native form of HBsAg. Both antibodies reacted with HBsAg in the hepatocyte of patient infected with hepatitis B virus. Analyses of the nucleotide sequences encoding the variable regions of these antibodies revealed that S2E1 and S2C11 utilize variable gene segment which belong to V4/5 gene family and utilize the J5 and Jk4 gene segments, respectively. In addition, the heavy chain of S2E1 express a member of V14 gene family and a member of DSP2.9 and Jh3 gene families. S2C11 is related to the V1 gene family and expresses DFL16.1 gene regions in conjunction with the Jh3 gene segment.
Subject(s)
Humans , Antibodies , Antibodies, Monoclonal , Base Sequence , Clone Cells , Cloning, Organism , Hepatitis B Surface Antigens , Hepatitis B virus , Hepatitis B , Hepatitis , HepatocytesABSTRACT
Objective:To clone Fab genes of anti-p185 monoclonal antibody 5E12 and express it in E.coli.Methods:Fd and ? genes were cloned by RT-PCR, inserted into Fab expression vector and expressed in E.coli. The N-terminal sequences of V regions was resumed by PCR mediated mutagenesis. The antigen-binding activity of the Fab were tested by ELISA and immunohistochemistry.Results:Fd and ? genes were cloned and expressed in E.coli. But the bacterially expressed Fab fragments showed no antigen binding activity. After the N-terminal sequences of V regions was corrected to original sequences, the Fab expressed in bacterial was able to target HER2/neu-expressing cells(NIH3T3/erbB-2 cells). Correction of Fd N-terminal sequences could partially resume the antigen binding activity. But correction of ? chain N terminal sequences was shown no expected result.Conclusion:Successful in constructing and expressing anti-p185 Fab, which will benefit the construction of other engineering antibody and humanization of murine anti-p185 McAb. We also found that the V region N terminal changes introduced with PCR primers may affect antigen binding activity seriously, to which more attention should be paid during antibody engineering.
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Objective: To clone the Fab gene of a monoclonal antibody (mAb) BDI against human bladder cancer and its expression in E. coli. Methods: Fd and K genes of mAb BDI were cloned by RT-PCR and inserted into an Fab expression vector. Phage displaying Fab and soluble Fab were expressed in E. coli. The N-terminal sequence of VH region was corrected by PCR mediated mutagenesis. The antigen-binding characteristics of the Fab were tested by ELISA and immu-nohistochemistry. Results: Fd and K genes were cloned into the expressing vector p3MH and the phage displaying antibody and soluble Fab were expressed in E. coli, which showed weak binding activity to bladder cancer cells. Correction of the N-terminal sequence of the VHimproved the biding activity dramatically. The feasibility of the application of the Fab in phage antibody library screening was confirmed by a simulated panning procedure. Conclusion: The Fab gene of an anti-human bladder cancer mAb was expressed in E. coli. The importance of the N-terminal sequence on antibody binding activity was suggested.