text: Cell culture and stimulation
  All cell lines were maintained at 5% CO2 in RPMI 1640 medium with 1% glutamine (Gibco/BRL Eggenstein, Germany) supplemented with 10% fetal calf serum (Gibco/BRL), 1% penicillin/streptomycin (Biochrom, Berlin, Germany). When indicated, cells were treated with 5-aza-2-deoxycytidine (AzadC) or 5-azacytidine (AzaC) (Sigma, Taufkirchen, Germany) for different time periods. Owing to their chemical instability fresh substances were re-added every 24 h. 
  