CHARACTERIZATION OF A NEW IL-6- DEPENDENT HUMAN B-LYMPHOMA CELL LINE IN LONG TERM CULTURE Glenn H. Bock,*? Clarisa A. Long,* Monica L. Riley,* Jeffrey D. White,* Carole C. Kurman,* Thomas A. Fleisher,$ Maria Tsokos,$ Margaret Brown,$ Debbie Serbousek,” William D. Schwietermann,” David L. Nelson* We have established a cell line (D&l) of B-cell lineage in long-term culture. It was derived from an immunodeficient patient with intestinal lymphangiectasia and lymphoma by cultur- ing malignant pleural effusion cells with IL-6 in vitro. The cell surface phenotype was: PCA- 1, HLA Class II(+); CD25, CD19, CD20, CD30, CD38(-). Cell proliferation was poor in medium and exhibited an eight-fold, dose-dependent increase of proliferation in response to t-IL-6 of human but not murine origin. The secretion of IgG into culture supernatants by DS- 1 was not enhanced by rIL-6. While constitutive production of IL-6 was not detected by bioassay using murine B9 hybridoma cells or by ELISA, the presence of IL-6 message was detected in polyA+ selected mRNA by Northern analysis. Spontaneous proliferation of DS-1 cells was inhibited by neutralizing polyclonal antibodies to IL-6 (37%) and mAb to IL-6 (54%) and IL-6R (53%). DS-1 expressed both high and low affinity IL-6 receptors (& 1.2 X lo-l1 and 6.7 X IO-l’, respectively) by radiolabelled binding and Scatchard analysis. Thus, DS-1 represents an autocrine ILd-producing cell line of B-cell lineage which resembles lymphoid malignancies arising in patients with AIDS and other immunodeficiency diseases. Despite constitutive IL-6 production, the in vitro growth of DS-1 is dependent upon exogen- ous IL-6. DS-1 may thus be useful as a model of IL-6 dependency. This cell line may also facilitate development of strategies for diagnosis and treatment of B-cell lymphomas in immunocompromised patients. There is accumulating evidence to support the importance of IL-6 as a multifunctional growth and differentiation factor in an increasing number of bio- logical systems. The induction of IL-6 secretion and its subsequent actions primarily occur in response to infectious and inflammatory events. Included in the repertoire of IL-6 activities are enhancement of B-cell From the *Metabolism Branch, DCBDC, National Cancer Insti- tute, N.I.H., Bethesda, MD, USA; TDepartments of Nephrol- ogy, Children’s National Medical Center and Pediatrics, George Washington University School of Medicine, Washington DC, USA; $Immunology Service, Clinical Pathology Department, N.I.H., Bethesda, MD, USA; and SLaboratory of Pathology, National Cancer Institute, N.I.H., Bethesda, MD, USA. Correspondence to: Glenn H. Bock, M.D., Fairfax Hospital for Children Kidney Center, 3300 Gallows Road, Falls Church, VA 22046, USA. Received 22 July 1992; accepted for publication 19 March 1993. 0 Academic Press Limited. 1043-4666/93/050480+10 $08.00/O KEY WORDS: immune deficiency/IL-6/IL-6 receptors/intestinal lymphangiectasia/lymphoma/cell line 480 immunoglobulin synthesis,132 induction of T-cell acti- vation expression of the hepatic acute phase reac- tion4 and stimulation of haematopoietic progenitor cell proliferation.5 The regulation of most normal IL-6 stimulatory activity appears to occur in concert with other cyto- kines. However, recent reports have described direct IL-6-induced proliferation in certain human tumour cells and tumour lines, particularly of myeloma/plas- macytoma lineage. 6-x This supports the notion that IL-6 can function as a myeloma growth factor and that dysregulated, autocrine IL-6 production may occur in these conditions. Herein, we report our studies of the growth characteristics and IL-6-dependency of a newly established cell line derived from a B-cell lym- phoma which arose in a patient with intestinal lym- phangiectasia. Furthermore, we discuss the possible relevance of this cell line to future studies of human IL-6 physiology as well as of malignancies of B-cell lineage occurring in association with other acquired and inherited immunodeficiency states. CYTOKINE, Vol. 5, No. 5 (September), 1993: pp 480-489