Patent ID: 7491530

Claim:
A mouse B-lineage fusion partner cell comprising at least two ectopically expressed exogenous nucleic acid molecules, wherein (a) each of the ectopically expressed nucleic acid molecules encodes a polypeptide that when expressed in a hybrid cell formed by the fusion of the fusion partner cell and a human B-lineage fusion cell, alters the phenotype of the hybrid cell; (b) one of the at least two encoded polypeptides is IL-6 or IL-11, and one of the encoded polypeptides is hTERT; and (c) the fusion partner cell is characterized in that fusion of the fusion partner cell with the human B-lineage fusion cell results in a hybrid cell that displays enhanced stability of antibody expression upon cloning of the hybrid cell, relative to the stability of antibody expression that would be observed if the fusion partner cell ectopically expressed IL-6 or hTERT but not both.