Cell line and culture maintenance
The Chinese Hamster Ovary (CHO) cell line expressing human monoclonal anti-Interleukin-1β IgG1 (Kennard et al., 2009) ChK2 437.89.34 was provided by Pfizer (St. Louis, MO). The cell line was maintained in shake tubes (Corning or Nalgene) in a humidified incubator (Kuhner shaker, Basel, Switzerland) at 37˚C, 5% CO2 and 225 rpm. The cells were passaged every 3 days and grown in chemically defined CD CHO medium (Gibco-Invitrogen, Grand Island, NY), supplemented with 100 µg/mL hygromycin B (Gibco), 4.5 µg/mL bleocin (Calbiochem, La Jolla, CA) and 4 mM glutamine (Gibco).