EXPRESSION OF AN EXOGENOUS INTERLEUKIN-6 GENE IN HUMAN EPSTEIN-BARR VIRUS-B CELLS CONFERS GROWTH ADVANTAGE AND INVIVO TUMORIGENICITY

The biological role of interleukin 6 (IL 6) molecules in human B cell tumorigenesis was studied by using an episomal expression vector, pHEBoSVIL6, to introduce stably the human IL6 gene into human Epstein Barr virus (EBV)-transformed B lymphoblasts. The gene was present in the IL6-transfected cells in a high copy number and was efficiently expressed, resulting in the secretion of consistent levels of 11,6 molecules. The constitutive expression of the IL6 gene led to an altered pattern of growth and to a malignant phenotype, as shown by clonogenicity in soft agar cultures and tumorigenicity in nude mice. These data suggest that the combined action of EBV, which exerts an immortalizing function, and of the growth-promoting activity of IIr6 molecules, can give rise to fully transformed B cell tumors in immunodeficient subjects. © 1990, Rockefeller University Press., All rights reserved.