Monoclonal antibodies Epstein-Barr virus-transformed

Antibodies are expressed by hybridoma cells formed by cell fusion of sensitized animal or human B lymphocytes with myeloma cells, or they are generated by EBV (Epstein-Barr virus) transformation of sensitized B lymphocytes. Other heterologous expression systems such as bacteria, yeast, insect cells, and mammalian cells have also been used for expression of antibodies and their fragments. However, because of renaturation problems, glycosylation, and expression levels, mammalian cells are mostly used for the expression of monoclonal antibodies. More recently, technologies have been extensively developed for the expression of antibodies in transgenic animals and transgenic plants. 

Buchacher, A., Predl, R., Strutzenberger, K., Steinfellner, W., Trkola, A., Purtscher, M., Gruber, G., Tauer, C., Steindl, F., and Jungbauer, A. (1994). Generation of human monoclonal antibodies against HIV-1 proteins electrofusion and Epstein-Barr virus transformation for peripheral blood lymphocyte immortalization. AIDS Res. Hum. Retroviruses 10, 359-369. 

Although Epstein-Barr virus (EBV) is capable of inducing cellular transformation, few antibody-producing B lymphocytes display the viral cell surface receptor. Most, therefore, are immune to EBV infection. Even upon successful transformation, most produce low-affinity IgM antibodies, and the cells are often unstable. Having said that, one monoclonal antibody approved for medical use (Humaspect, Table 10.4) is produced by a human lymphoblastoid cell line originally transformed by EBV. 

An immunogen induces antibodies from many B cell clones, producing a polyclonal antibody response. In contrast, the propagation of an isolated B cell clone produces an antibody of single specificity. However, the problem is that in tissue culture medium, B cells die within a few days of their isolation from, for example, a mouse spleen. To circumvent this problem, immortality can be conferred on B cells by means of viral transformation Epstein-Barr virus can be used. Alternatively, fusion to cancerous cells is carried out to generate hybrids or hybridomas. Generally, the former procedure is used to immortalize peripheral blood B cells and produce human monoclonal antibodies, while myeloma cells are used to produce murine monoclonal antibodies. 

Normal B cells are incapable of extended growth outside the animal. The production of monoclonal antibodies, however, involves establishment of a B cell clone producing the antibody in long-term culture. This is accomplished by immortalizing the B cell using a transforming virus such as the Epstein-Barr virus... 

Epstein-Barr virus (EBV)-transformed homozygous human B-cell lines were used as a source for isolating HLA class II molecules. In the case of isolation of HLA-DR1, WT-100 cell pellets were lyzed by NP-40, and DR1 was isolated from homogenates by affinity chromatography with the monoclonal antibody L243 essentially as described [64,65].The purity of the preparation was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), HPSEC and Western blotting. 

HA-IA (Centoxin Centocor, Malvern, PA) is a human IgM monoclonal antibody that binds to the lipid A domain of endotoxin and is produced by the stable heteromyeloma cell line A6(H4C5). This hybridoma was created by fusion of a murine-human heteromyeloma line with splenic B lymphocytes sensitized in vivo by immunization with killed Escherichia coli J5 cells and subsequently transformed in vitro by Epstein-Barr virus. 

---