Recombinant single chain Fv antibody fragment and its use in the immunopurification of the recombinant Hepatitis B Virus Surface Antigen

摘要

A recombinant single chain Fv (scFv) antibody fragment specific for the Hepatitis B virus surface antigen (HBsAg). Production of the scFv fragment in Escherichia coli using recombinant DNA technology. The scFv can substitute the mouse monoclonal antibody (MAb) CB-Hep.1 that is used in one of the purification steps of a known production process of such antigen. The scFv antibody fragment is developed using recombinant DNA technology, by cloning and modifying the genes that code for the heavy and light chain variable regions of MAb CB-Hep.1. The scFv fragment is specific for the HBsAg, has smaller size than the MAb, and is produced from bacterial cultures (E. coli). The scFv is purified from material harvested from these cultures and immobilized on chromatographic supports for its use as immunoabsorbent in the purification of the recombinant HBsAg that is employed as active raw material of a vaccine preparation. Due to its specificity for the HBsAg, the fragment can be employed also in immunoassays in which the HBsAg is recognized or detected. Part of the protein sequence of the heavy chain variable region of MAb CB-Hep.1 may be used to construct fusion proteins for expression in E. coli that will associate with the bacterial inner membrane, facilitating in this way their purification process.