Production of Human Monoclonal Antibodies Against FC Epsilon Receptor I Alpha by Combining In Vitro Immunization with Phage Display

Abstract

An in vitro immunization protocol using human peripheral blood mononuclear cells (PBMC) was developed to generate human antigen-specific antibodies. Monoclonal antibody has a great potential, especially efficient acquirement of monoclonal antibodies against membrane proteins provides advantages. In this study, we tried to generate a human monoclonal antibody against the high affinity IgE receptor, FcɛRIα, using a method combining in vitro immunization and phage display. Heavy and light chain variable region genes were obtained from PBMC immunized in vitro with FcɛRIα-expressed KU812F cells. Subsequently a combined phage antibody library of 6 × 103 size was generated. Antigen-specific phage antibody clones were selected by panning with recombinant FcɛRIα and recombined to produce human IgG format antibodies using CHO cells. The antibodies exhibited specific binding against FcɛRIα. These results demonstrated that we could obtain membrane protein-specific human monoclonal antibodies from a relatively small phage antibody library using in vitro immunized PBMCs.