Differentiation of human induced pluripotent stem cells to authentic macrophages using a defined, serum-free, open-source medium.

Human induced pluripotent stem cells (iPSCs) and macrophages derived from them are increasingly popular tools for research into both infectious and degenerative diseases. However, as the field strives for greater modeling accuracy, it is becoming ever more challenging to justify the use of undefined and proprietary media for the culture of these cells. Here, we describe a defined, serum-free, open-source medium for the differentiation of iPSC-derived macrophages. This medium is equally capable of maintaining these cells compared with commercial alternatives. The macrophages differentiated in this medium display improved terminally differentiated cell characteristics, reduced basal expression of induced antiviral response genes, and improved polarization capacity. We conclude that cells cultured in this medium are an appropriate and malleable model for tissue-resident macrophages, on which future differentiation techniques can be built.