Expression of Human Neutralizing Recombinant scFv-Fc Fusion Antibody to Hepatitis A Virus in Pichia pastoris
The recombinant human neutralizing monoclonal antibody pPiscFv-FcHA16 against hepatitis A virus (HAV) was expressed in Pichia pastoris. The heavy and light chain variable genes of human-derived neutralizing scFv antibody against HAV were cloned into Pichia pastoris expression vector, which already has the signal peptide and human IgG1 Fc fragments fused in it in frame. The pPiscFv-FcHA16 fusion antibody product was purified from the culture medium and well characterized. The expressed pPiscFv-FcHA16 fusion antibody can form a homodimer with different glycosylations. When compared with the same IgG molecule expressed in CHO cells, the expressed pPiscFv-FcHA16 fusion antibody fully retained the specificity of binding to HAV and competition with mouse neutralizing anti-HAV McAb using ELISA, and also retained viral neutralizing activity in vitro. The results of this study demonstrated that the scFv-Fc fusion antibody expressed in Pichia pastoris well retained the biological activities when tested in vitro, pointing to the feasibility of producing scFv-Fc fusions in Pichia pastoris for diagnosis and for purification of antigen in vitro and the possible therapeutic use.