Monocytes were enriched from peripheral blood mononuclear cells from three healthy donors using Rossette Sep Monocyte enrichment cocktail through Ficoll separation (STEMCELL Technologies, Vancouver, Canada) as previously described (22 (link)). Purified monocytes were then differentiated in X-vivo15 medium (Lonza, Walkersville, MD, USA), with GMCSF 1000U/ml and IL4 1000U/ml (Pepro Tech Inc, Rocky Hill, NJ, USA) with the change of media every other day.