The EL-4 murine lymphoma cell line was purchased from American Type Culture Collection (ATCC) and grown in Dulbecco's Modified Eagle's Media supplemented with 10% Fetal Bovine Serum and 1 % Penicillin Streptomycin. Cells were cultured in Corning T-175 flasks at 37°C in a humidified atmosphere containing 5% CO2. Cultures were maintained at 10 5 -10 6 cells/ml by addition of fresh media every 2 days.