Expansion of human iNKT cells from PBMCs

Human iNKT cells were expanded from resting PBMCs of healthy donors as described before [41 (link)]. Briefly, freshly isolated PBMCs (1 x 10⁶ cell/ml, 5 ml/well) were treated with 100 ng/ml αGalCer (KRN7000, Avanti Polar Lipids) and cultured for 13 days. 20 IU/ml human recombinant IL-2 (Proleukin, Novartis, Basel, Switzerland) was added to the cultures every other day starting from day 2. From day 6 onwards, the concentration of IL-2 was increased to 40 IU/ml. At the end of the expansion, an aliquot of each sample was collected and analysed for iNKT cell expansion by flow cytometry. Expansion was done in RPMI 1640 (Gibco, Waltham, MA, USA, or Lonza, Basel, Switzerland) supplemented with 5% (v/v) Human AB serum (Sigma-Aldrich, St. Louis, MO, USA), 1% (v/v) Penicillin/Streptomycin, 1 mM sodium pyruvate (Lonza), 1% (v/v) non-essential amino acids (Cegrogen Biotech, Stadtallendorf, Germany), 15 mM HEPES buffer (Sigma-Aldrich), and 55 μM 2-mercaptoethanol (AppliChem, Darmstadt, Germany).