Immunoglobulin transcripts and molecular history of a hybridoma that produces antibody to carcinoembryonic antigen

Hybridoma CEA 66-E3 secretes only an antibody directed against human carcinoembryonic antigen (CEA). This hybridoma has been used as a source of mRNA for molecular cloning studies, and for the bacterial expression of anti-CEA heavy and light chains [Cabilly, S. et al., Proc. Natl. Acad. Sci. USA 81 (1984) 3273-3277]. We report here nucleotide sequence data which indicate that hybridoma CEA 66-E3 produces significant levels of several immunoglobulin transcripts in addition to those of anti-CEA. One kappa-chain transcript can be traced back to MOPC21; other transcripts probably come from genes derived from the antigen-stimulated normal lymphocyte. This information should be especially relevant for many hybridomas in which the immortalizing fusion partner is a derivative of MOPC21, for example, X63-Ag8,SP/0-Ag14, or NS1n.