Myeloma cell, antibodies

Monoclonal antibodies are derived from a single, monospecific B cell clone. Monoclonal antibodies can be obtained from hybridoma cells that result from the fusion of antibody-producing B cells with immortal cells of a myeloma cell line. 

Monoclonal antibody technology entails isolation of such B-lymphocytes, with subsequent fusion of these cells with transformed (myeloma) cells. Many of the resultant hybrid cells retain immortal characteristics, while producing large quantities of the monospecific antibody. These hybridoma cells can be cultured long term to effectively produce an inexhaustible supply of the monoclonal antibody of choice. 

Fusion of human lymphocytes with human lymphoblastoid cell lines is a very inefficient process. Fusion of human lymphocytes with murine myeloma cells lead to very unstable hybrids. Upon fusion, preferential loss of human genetic elements is often observed. Unfortunately, particularly common is the loss of chromosomes 2,14 and 22, which encode antibody light and heavy chain loci. The production yields of human monoclonals upon immortalization of the human B-lymphocyte (by whatever means) are also low. 

The next development was the production of monoclonal antibodies (MAbs) in the mid-1970s. This uses hybridoma technology, which involves the fusion of antibody-producing B cells to immortal myeloma cells. Figure 4.4 shows the preparation of MAbs using hybridoma techniques. A more detailed discussion of biopharmaceuticals production is presented in Section 10.5. 

Fuii Human Antibody Full human antibodies are the current engineered antibodies. Several techniques are used to construct these antibodies. One method is to fuse human B cells to myeloma cells. These hybridomas will produce fully human MAbs. Another method is to genetically alter mice in the laboratory to contain human antibody producing genes. In response to antigens, antibodies resembling the human antibodies are produced. 

To obtain MABs, lymphocytes isolated from the spleen of immunized mice (1) are fused with mouse tumor cells (myeloma cells, 2). This is necessary because antibody-secreting lymphocytes in culture have a lifespan of only a few weeks. Fusion of lymphocytes with tumor cells gives rise to cell hybrids, known as hybridomas, which are potentially immortal. 

Spleen-derived B lymphocytes are then incubated with mouse myeloma cells in the presence of propylene glycol. This promotes fusion of the cells. The resultant immortalized antibody-producing hybridomas are subsequently selected from unfused cells by culture in a specific... 

As noted, one of the remaining challenges in obtaining human hybridoma cells for generahng human monoclonal antibodies is the lack of suitable human myeloma cell lines to generate stable hybrid cells that can be cloned and expanded indefinitely in culture. Many human hybridoma... 

Karpas, A., A. Dremucheva, and B.H. Czepulkowski, A human myeloma cell line suitable for the generation of human monoclonal antibodies. Proc Natl Acad Sci USA, 2001. 98(4) 1799-804. 

In MAB technology, the objective of the fusion process is to produce hybrid cells that incorporate the immortal characteristics of the myeloma cell with the antibody secreting properties of the antigen-sensitized lymphocytes. 

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