Generation and cloning of stable human IgE-secreting cells that have rearranged the C epsilon gene.

Although the secretion of Ig isotypes other than IgM is generally accompanied by a DNA rearrangement that deletes C mu (and the other IgCH genes located between VDJ and the expressed CH gene), a system has recently been described that generates a high frequency of IgE-secreting cells that have failed to delete IgCH genes or to rearrange their C epsilon genes. These cells, derived from EBV-transformed human PBMC, secrete IgM and IgD as well as IgE. To determine whether the absence of C epsilon rearrangement and CH gene deletion is a general phenomenon for human IgE-secreting cells, we have characterized IgE-secreting cells that are generated by culturing purified human B cells with EBV plus IL-4 in the presence of irradiated human PBMC. In contrast to the earlier observation, we have not been able to detect any cells that demonstrate cytoplasmic staining for IgE and concurrently stain for a second Ig isotype. Stable IgE-secreting cell lines and clones produced by this method have rearranged one of their C epsilon genes and have deleted both C mu genes. These observations demonstrate that the generation of human IgE-secreting cells can involve the same gene rearrangement and deletional mechanisms that lead to the generation of cells that secrete other isotypes.