Anti Cd <sub> 3 </ Sub> Genetically Engineered Chimeric Antibodies

Engineered antibody molecules and their fragments are being increasingly exploited as scientific and clinical tools. Gene recombinant technology allows them to be altered and creates novel improved molecules. Anti-CD₃ monoclonal antibody has been proved a kind of safe and effective immune regulator and used for the treatment of organ allograft rejection.autoimmune diseases, tumor and infectious disease caused by virus or parasite.The goal of this study is to construct chimeric anti-CD₃ antibody fragment and intact immnoglobulin molecule with improved properties in order to promote their therapeutic effects and minimize the side effects by recombinant DNA technology.1 Cloning of VH and VL genes of anti-CD₃ antibody and construction of phage display libraryTotal RNA was extracted by the one-step method from HIT3a hybridoma cell line secreting anti-CD₃ murine antibody. The first-strand cDNA generated by oligo(dT)₁₂ primer was used as templat to amplify the genes of variable region of heave chain(VH) and light chain(VL). The scFv gene fragment was constructed by overlap PCR with (G₄S)₃ linker and cloned into the vector pCANTAB 5E to construct the library of anti-CD₃ scFv phage antibody.The library was screened by panning using CD₃⁺ Jurkat cells as target cells and the clones binding to CD₃ specificlly were enriched from the primary library by panning. The BstNl fingerprints of PCR product indicate that the library of phage antibody was uniform after the fifth round of panning Eight clones were selected to prepare recombinant antibody and three clones were sequenced.The result displays that all the genes of that three clones had the same sequences and accorded...