The Conversion of Human Tissue-Like Inflammatory Monocytes Into Macrophages

Classical circulating LyC6^high murine monocytes differentiate progressively from inflammatory tissue monocytes to mature macrophages (Mϕ) after entry into gut mucosa. This protocol provides a two-step in vitro culture method that replicates the human monocyte maturation cascade. First, purified circulating CD14⁺ CD16^- monocytes exposed to granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon gamma (IFNγ), and interleukin 23 (IL-23) differentiate into tissue-like inflammatory monocytes. Next, addition of transforming growth factor beta (TGFβ) plus interleukin 10 (IL-10) promotes their maturation into tissue-like Mϕ. Methods to sort these cells after culture are also provided. The fine-tuning of this system might open therapeutic avenues for chronic inflammatory disorders. © 2021 Wiley Periodicals LLC Basic Protocol 1: Isolation of human monocytes from peripheral blood Basic Protocol 2: First step culture for generation of inflammatory monocyte-like cells Basic Protocol 3: Second step culture for differentiation of inflammatory monocyte-like cells into macrophages Alternate Protocol: Sorting and culturing of inflammatory monocyte-like cells.