Prokaryotic expression of gene of single chain variable fragment A7

OBJECTIVE To make a single chain variable fragment ScFv A 7 of antibody against the main immunogenic region MIR of acetylcholine receptor AChR as biological agent for the gene therapy in myasthenia gravis MG . METHODS The prokaryotic expressed recombinant vector bearing ScFv A 7 genes,constructed previously,was transformed in E.coli HB 2151 for expression of ScFv A 7 proteins in the periplasm induced by isopropyl thiogalactoside IPTG .The periplasmic fraction was made using sodium borate,and determined for the expression of ScFv A 7 protein by dot blot assay using a mouse monoclonal antibody against c-myc, a tag connected and co-expressed in the ScFv A 7. RESULTS ScFv A 7 proteins were found in the periplasmic fraction,whereas,no ScFv A 7 was detected in the culture medium or in control E.coli HB 2151. CONCLUSION The ScFv A 7, an antibody fragment against AChR MIR in MG,is successfully expressed in the prokaryotic cells.