Antigen-presenting-cell (APC) gating strategy. (A) Single, viable PBMCs positive for HLA-DR and negative for the lineage markers CD3, CD19, and CD56. FSC, forward scatter; SSC, side scatter. (B) HLA-DR+ CD3− CD19− PBMCs were distinguished into CD14+ monocytes and CD14− APCs. (C) Monocytes were subdivided based on CD16 expression into CD14+ CD16− classical monocytes (I) and CD14+ CD16+ intermediate monocytes (II). (D) CD14− APCs were gated based on CD16 expression to distinguish CD14 CD16+ myeoloid dendritic cells (DCs) (III) (CD16 mDCs). (E) CD14− CD16− APCs were further subdivided into CD14− CD16− CD1c+ (IV) (type 1 myeloid DC [CD1c mDCs], also known as BDCA1 mDCs), CD14− CD16− BDCA3+ (V) (type 2 mDCs or BDCA3 mDCs), and CD14− CD16− BDCA2+ (VI) (plasmacytoid DCs [pDCs]).