The human hybridoma technique offers an important approach for isolation of human monoclonal antibodies. A diversity of approaches can be used with varying success. Recent technical advances in expanding the starting number of human antigen-specific B cells, improving fusion efficiency, and isolating new myeloma partners and new cell cloning methods have enabled the development of protocols that make the isolation of human monoclonal antibodies from blood samples feasible. Undoubtedly, additional innovations that could improve efficiency are possible.
HISTORY OF HYBRIDOMASMonoclonal antibodies (mAbs) have revolutionized the conduct of science since their first description in 1975 (1). The use of these specific reagents also has made possible improved clinical diagnostics in the medical arena, and many antibodies have found their way to clinical use as prophylactic or therapeutic agents. Nevertheless, the potential of mAbs derived specifically from technology based on human hybridomas remains largely unfulfilled. The principal reason for the lack of a large number of hybridoma-derived mAb therapeutics has simply been the technical difficulty in generating stable hybridomas that secrete human mAbs of high affinity and functional activity. This chapter reviews recent efforts to develop and employ novel methods for the efficient generation of human hybridomas secreting human mAbs for clinical use.The principal advantage of the use of human hybridoma technology for mAb generation is that this approach preserves the authentic sequence and pairing of antibody DNA from a natural B cell for the expression of a naturally occurring full-length human mAb. There are significant theoretical advantages for expressing cDNAs encoding authentic heavy and light chains with chains that are paired using the coding sequence as it was generated naturally through B cell selection, class switch, and affinity maturation. No genetic modification of these sequences is required. Since antibody expression is typically very stable in hybridomas, sequence amplification of antibody variable genes is achieved easily if recombinant production or manipulation is desired. The resulting recombinant mAb retains most features of naturally occurring human antibodies, as the clone retains the native amino acid sequence and heavy/light chain pairing. Since the native constant region of the antibody in the original human B cell is retained in the mAb expressed by the resulting hybridoma, the functional properties of the particular Fc region can be studied for Fc-mediated activities, such as antibodydependent cellular cytotoxicity.