Principle and application of somatic cell mutation based autonomously diversifying library system for monoclonal antibody preparation

Autonomously diversifying library is a newly established system which can produce antibody based on somatic mutation.The mechanism is targeted on DT40 (DT40 is an avian leukosis virus induced bursal lymphoma cell line derived from a Hyline SC chicken, expressing membrane bound and secretion forms of chicken IgM). Trichostatin A was used to inhibit acetyl active enzyme of DT40.This in turn promotes the histone acetylation, resulting in immunoglobulin gene frequent conversion, and the display of membrane combined IgM library on the surface of cell.Finally, antigen tag magnetic separate method was used to select chicken source cells with antigen specific antibody from the library.Subsequent cell culture was used to acquire secretory monoclonal antibody IgM.Then, by inserting the DNA sequence of human IgG Fc fragment into the corresponding region of IgM heavy chain in DT40 cells, we can establish the ADLib system which synthesizes the chimeric human IgG with chicken Fab and human Fc (Fc fragment decides the type of immunoglobin heavy chain). ADLib system can be applied to the production of diagnostic and therapeutic monoclonal antibody drugs. Key words: Autonomously diversifying library; Trichostatin A; Monoclonal antibody; Human chimeric antibody