The role of BM stromal cell contact in the growth of BLIN-2. BLIN-2 cells cryopreserved in February 1995 and thawed for use in this experiment in January 1998 (A) or maintained continuously on BM stromal cells (B) were cultured in direct contact with BM stromal cells, in transwell inserts (noncontact) suspended above the BM stromal cells, or in medium alone. BLIN-2 growth was quantified on days 7, 11, or 15. Each symbol represents the mean ± SD of triplicate wells. This experiment is representative of six similar experiments.