Affiliations: Department of Hybridoma and Tissue Culture, Central Laboratory of the Netherlands Red Cross Blood Transfusion Service, and Laboratory for Clinical and Experimental Immunology of the University of Amsterdam, Amsterdam, The Netherlands
Note: [] Address reprint requests to: Dr. W.P. Zeijlemaker, Central Laboratory of the Netherlands Red Cross Blood Transfusion Service, P.O. Box 9406, 1006 AK Amsterdam, The Netherlands.
Abstract: To optimize growth and Ig production of in vitro-cultured Epstein-Barr virus (EBV)-transformed B cells, a panel of six monoclonal EBV B-cell lines was analyzed for autocrine growth factor production and responsiveness to various cytokines. Three cell lines produced Il-1 and four produced Il-6, although differences concerning the amount of lymphokines produced were observed. Interestingly a considerable tumor necrosis factor β (lymphotoxin) activity was found in supernatants of all cell lines. One IgM-producing cell line that did not secrete either Il-1 or Il-6 was exceptional in its ability to respond to the addition of rIl-6 with a 5- to 10-times elevated IgM production. In contrast, cell lines in the panel capable of Il-6 production showed only a minimal elevation of Ig production on addition of exogenous Il-6. Ig production was slightly less in some cell lines when Il-6 was neutralized. Antibodies against lymphotoxin or Il-6 did not influence growth rate of the cell lines significantly, implying that neither Il-6 nor lymphotoxin had an autostimulatory effect on the analyzed cell lines. This study demonstrates a heterogeneity regarding the amount and type of lymphokines produced by long-term monoclonal EBV cell lines, which may account for the diverse responses exhibited by these cells towards exogenously added lymphokines.
