Myeloma cells, hybridomas grown from

Fig. 3. To produce monoclonal antibodies, antibody producing spleen cells troll] a mouse that has been immunized against an antigen am mixed with mouse myeloma cells. Under the proper conditions, pairs of the cells fuse to form antibody-producing hybrid-myeloma ( hybridoma ) cells, which can live indefinitely in culture. Individual hybridomas are grown in separate wells, and the antibodies they produce are tested against the antigen. When an effective cell line is identified, it is grown either in cuhure or in the body cavities of mice to produce large quantities of chemically identical, monoclonal antibodies (reprinted with permission from Olsen, 1986, p. 26, Copyright, National Academy Press)...

The problem is that if an individual antibody-producing cell is isolated and grown in culture, its descendants have a limited lifespan that severely limits their use for the routine preparation of monoclonal antibodies. In 1975, Milstein and Kohler discovered how monoclonal antibodies of almost any desired antigen specificity can be produced indefinitely and in large quantities. Their method was to fuse a B lymphocyte producing antibody of the desired specificity with a cell derived from a cancerous lymphocyte tumor, called a myeloma cell, which is immortal. The cell fusion is called a hybridoma, which is both immortal and secretes the same specific antibody originally encoded by the B lymphocyte. 

Several satisfactory plasmacytoma cell lines are available (Table 5.3). All the early lines produced myeloma proteins, so that hybridomas secreted three types of Ig the original myeloma proteins, the specific antibodies, and hybrid molecules. The X63 plasmacytoma, which produces a fully sequenced IgGl, was used in the original technique of Kohler and Milstein (1975). These X63 cells may undergo spontaneous fusion with each other and can be grown at very low cell densities making it relatively easy to clone hybrids. Several variant lines have been selected from this line (NS-1, Sp2, FO) some of which do not synthesize or secrete heavy or light chains. Sp2... 

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