Effect of IL-6 on proliferation and IG production of human EBV-transformed cell lines in serum free culture media

To optimalize growth and Ig production of EBV transformed B cells for large scale tissue culture, we analyzed five stable monoclonal EBV-B cell lines for their responsiveness to interleukin (IL)-6 in standard medium with 5% FCS and in several serum-free media. As we previously demonstrated these cell lines were found to be heterogeneous with regard to their production of Il-1, Il-6 and lymphotoxin. We could not demonstrate an effect of Il-6 on proliferation on any of the cell lines in either standard medium with 5% FCS or in any of the serum-free culture media. In standard medium, cell lines capable of Il-6 production showed a slight elevation of Ig production in response to exogenous Il-6. Only one cell line, that did not secrete any of the lymphokines tested, responded strongly to Il-6 with a 12 times elevated IgM production. In contrast, in serum-free medium supplemented with Bovine Serum Albumin (BSA), Il-6 raised Ig secretion of all cell lines. This study shows that in some serum-free culture media EBV cell lines can be propagated as well as in standard medium with FCS. Responsiveness of these cells to cytokines is heterogeneous and is at least partially influenced by the culture medium used