Enhanced immune response of human iPSC-macrophages via animal-free manufacturing processes

Recent interest in macrophages derived from induced pluripotent stem cells (iPSC-Mac) has led to various differentiation protocols, often using undefined animal serum like fetal bovine serum (FBS). This study compared FBS-based media to the defined medium X-VIVO™ 15 containing human serum albumin (hSA).

Both produced functional macrophages, but those in hSA displayed a neutral activation state, enhanced cholesterol metabolism, and more significant changes in surface phenotype after stimulation. They also had a stronger response to co-stimulatory signals, making them better for testing immunomodulatory drugs. In contrast, FBS-grown macrophages were more adherent and pre-activated, showing reduced sensitivity upon stimulation, which may pose challenges for drug screening and immunomodulatory evaluations.