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Background

Macrophages are essential immune cells that play central roles in maintaining tissue health and coordinating inflammatory responses. Because of these diverse functions, they become valuable models for studying human disease and evaluating new therapeutic approaches. Human pluripotent stem cell (hPSC)-derived macrophages provide a renewable and more consistent alternative to primary cells, making them well suited for large-scale research applications. Despite these advantages, many differentiation protocols still rely on animal-derived culture components, introducing variability that can limit standardization and reproducibility.

Biolaminin contribution

In this study, van den Berk et al. investigated whether animal-derived culture components, such as Matrigel and fetal bovine serum (FBS), could be replaced with defined recombinant extracellular matrix proteins, including Biolaminin 521 (LN-521). Under defined animal origin-free culture conditions, the researchers efficiently differentiated hPSCs into CD14+ precursor macrophages that displayed comparable yields and phenotypes to conventional cultures across multiple independent stem cell lines. Biolaminin 521 also replaced FBS-coated substrates during macrophage maturation and polarization while maintaining differentiation efficiency and macrophage identity.

The differentiated macrophages retained the expected characteristics of mature macrophages throughout the workflow. They could be polarized into both pro-inflammatory and anti-inflammatory states while maintaining appropriate phenotype and function. This was confirmed through subtype-specific surface marker expression, cytokine and chemokine secretion profiles, and phagocytic activity. Notably, macrophages generated on Biolaminin 521 demonstrated enhanced phagocytic activity in several macrophage populations compared with conventional culture conditions, indicating that replacement of animal-derived components did not compromise cellular function.

To further improve standardization, the researchers replaced aggregate-based differentiation with a single-cell seeding approach on Biolaminin 521. This strategy generated precursor macrophages with comparable phenotypic and functional characteristics while providing greater control over the differentiation process and reducing culture-to-culture variability.

Clinical translation and future applications

These findings demonstrate that Biolaminin 521 can support a fully animal component-free macrophage differentiation workflow without compromising cell phenotype or function. By enabling reproducible generation of functional macrophages under defined culture conditions across multiple independent hPSC lines, this approach provides a standardized platform for immunological research, disease modeling, and drug discovery while supporting broader efforts to reduce reliance on animal-derived materials in accordance with the 3R principles.

Reference: van den Berk L. et al. Animal Component-Free Differentiation of Human Pluripotent Stem Cells into Macrophages. Stem Cell Research. 2026. DOI: 10.1016/j.scr.2026.103957

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