Cultures of mouse thymic stromal cells (OP9) expressing the human Delta-like ligand 1 (OP9-DLL1 cells) or control green fluorescent protein (GFP; OP9-GFP cells) (kindly provided by Graham Anderson, The University of Birmingham) were maintained for up to 20 passages in Opti-MEM medium (Gibco, Life Technologies) with 20% fetal calf serum (FCS).
BNHL-1 cells were derived from a bone marrow sample from a patient being treated for low-grade B cell non-Hodgkin's lymphoma (NHL). Cells of the BNHL-1 cell line were phenotypically the same as cells of the low-grade B cell NHL observed in the patient. These cells were infected with EBV and were continually maintained on the OP9-DLL1 cells, unless specified otherwise. An EBV-negative counterpart was maintained in the same manner.
293 cells containing recombinant wild-type EBV strain 2089 were maintained in RPMI, 10% FCS, and 100 μg/ml hygromycin. Akata cells containing recombinant wild-type EBV Akata were maintained in RPMI, 10% FCS, and 50 ng/ml G418.