Programmable synthetic cytokine receptors polarize macrophages to user-defined functional states

Technology that precisely controls macrophage polarization to distinct functional states would deepen our understanding of macrophage biology and enable the development of new macrophage cell therapies. Here, we use a synthetic cytokine receptor (SCR) platform with a programmable signaling domain to control the polarization of primary human macrophages. SCRs containing signaling motifs from the interferon-gamma (IFN-γ) or Interleukin-10 (IL-10) receptors mimic key features of pro-inflammatory or anti-inflammatory polarization, respectively. Random recombination of nine distinct signaling motifs to create new SCR signaling domains generates a diverse landscape of synthetic macrophage states with varied expression of inflammatory markers (CD80, CD40) and anti-inflammatory markers (CD163, CD206), and varied phagocytic capacity. SCRs programmed with multiple YLxQ motifs increase macrophage phagocytosis of E. coli and chimeric antigen receptor (CAR)-macrophage phagocytosis of cancer cells in mice, reducing tumor burden by 30-fold. The motif-dependent polarization is well-described by a two-state model, enabling quantitative prediction of macrophage polarization state from SCR signaling domain composition. Leveraging this model, we design an SCR that simultaneously enhances phagocytosis and maintains a macrophage pro-inflammatory state. Together, these findings establish a framework for synthetic programming of macrophage polarization states, with potential applications in cancer immunotherapy and other disease contexts.