High Affinity Human Monoclonal Antibody To Integrin Alpha4Beta7Screening And Functional Testing

Integrin is a kind of cell surface adhesion molecules which made up of αand β subunits heterologousdimers and belong to transmembrane protein.As a bridge between cell’s inside and outside, integrin on theone hand responsible for mediating the interaction between different cells, cells and the extracellularmatrix,cells and the pathogen; on the other hand, signals can be transfered across the cell membrane byways of outside-in or inside-out through integrin, these signals are very important for the immune response,immune cell positioning, blood coagulation, the organization and callus, development of cancer cells andtissues and organs.Integrin alpha4beta7is an adhesion molecule which are very important to theinflammation pathological process and lymphocyte migration movement. Integrin is one of kinds ofimportant lymphocytes homing receptors. It is the surface of B lymphocytes and T lymphocytes thatintegrin alpha4beta7mainly expressed on. It’s can regulate lymphocyte’s rolling and adhesionon the surfaceof thecellsin the vascular endothelial through the interaction between its ligand MAdCAM-1(mucosaladdressin cell adhesion molecule-1).The expression or conformation abnormalities of integrin associated with the process of inflammation.Such as the Inflammatory bowel disease, IBD is an inflammation of the colon and small intestine, mainlyincluding the Crohn’s disease and the ulcerative colitis, during the development of IBD often associatedwith the expression of integrin alpha4beta7rise and abnormal activation. After activation, integrinalpha4beta7will interact with its ligand MAdCAM-1. The interaction will promote the development ofdownstream signaling and then aggravate the inflammation.Therefore, in order to treat the inflammatorybowel disease, regarding integrin alpha4beta7and its ligands as drug targets has become the hot spot.People have regarded antibodies which could identify integrin alpha4beta7as a drug candidate, to treatrelated diseases.So, find specific inhibition of the activation conformation of integrinalpha4beta7will play agood curative effect in the treatment of IBD. The finding of high-affinity antibodiesthat can bind to integrinalpha4beta7is the fist step of findingother functional antibodies to integrin alpha4beta7. And the enrichmentof high-affinity antibodies to integrin alpha4beta7will also bring convenience to the research.LJF9scFv antibody fragments was selected from an human phage scFv antibody library.The LJF9scfvantibody fragments can identify integrin alpha4beta7with high affinity.We changed the scFv fragment of LJF9into full length IgG by inserted the heavy chain variable region and light chain variable region intothe heavy chainconstant region and light chainconstant region or human IgG1respectively. Then wecotransfect the full length heavy chain and light chain into eukaryotic expression system to express the IgGprotein, proteinA column were used to obtained the full length of monoclonal antibody protein. Finally, wetested the affinity ofLJF9IgG to integrin alpha4beta7by flow cytometry and find LJF9IgG antibodyhad ahigher affinity tobind integrin alpha4beta7.