The human immune system develops in waves, the first of which begins even before birth. Fetal and adult T cells originate from different stem-cell populations, allowing the fetal immune system to better tolerate foreign antigens — namely the mother's.
Joseph McCune at the University of California, San Francisco, and his colleagues compared human fetal blood stem cells and T cells with those of adults. After implantation in mice that permit human blood-cell maturation, fetal stem cells were more likely than adult ones to develop into regulatory T cells. These suppress immune activity, enhancing tolerance to antigens.
Fetal stem cells and T cells also had different gene-expression profiles from the adult versions of these cells. Statistical analysis revealed that developmental stage accounted for most of these differences.
Rights and permissions
About this article
Cite this article
Developmental biology: Immune system emerges in layers. Nature 468, 1005 (2010). https://doi.org/10.1038/4681005d
Published:
Issue Date:
DOI: https://doi.org/10.1038/4681005d