<p>An animal is immunized with the A chain and the B chain of a receptor and then mRNA is extracted from spleen cells of this animal. Next, the L-chain and H-chain variable regions are collected by RT-PCR with the use of primers corresponding to the variable regions including CDR. Single-strand Fv is synthesized by assembly PCR and thus a phage library is constructed. Next, antigen-binding antibody clones are concentrated and cloned by panning. The single-strand variable region is inserted between a signal sequence for animal cells and CH1-hinge-CH2-CH3 to prepare an scFv-CH1-Fc expression vector. By transferring various combinations of the vector into cells, antibodies are expressed and an antibody clone showing a ligand-like activity is selected.</p>
