Stable Transformed Cell Lines

Among the different gene transfer techniques, microinjection is by far the most efficient procedure. Only microinjection allows the transfer of a known number of test molecules either into the cytoplasm or into the nuclei of the recipient cell Up to 100% of the recipient cells support expression of the transferred material, and stable transformed cell lines can be isolated with a frequency of 20-30%. Biochemical studies can be performed with 50-100 injected cells, and the injected material (e.g., DNA, RNA) can be reisolated and further analyzed by standard techniques (e.g., Southern and Northern blots, electron microscopy) (for review, see Graessmann and Graessmann, 1983 Graessmann et al., 1983 Ceiis et al., 1986). 

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. 

This situation has now altered with increasing acceptance of alternative cell substrates, including both genetically manipulated and spontaneously transformed (but stable) cell lines for production processes. A good example is the WHO Vero... 

If it is found that the EBV-transformed B-LCL fed to grow rapidly or that they have lost antibody secretion, fusion of human B-LCL with mouse myeloma may be attempted to stabilize the cell lines. However, stable heterohybrids are more likely to be produced if B-LCL are fused at about a month after EBV transformation, rather than older cell lines. Human B-LCL or (less commonly) B cells have been fused with myeloma or (less often) heterohybridoma cell lines. Here the fusion of B-LCL with P3X63Ag8.653 is described (3, 7). 

---