Fetal Lung Immune

Early human lung immune cell development and its role in epithelial cell fate, Barnes et al 2023 Science Immunology, 2023

From birth, the airways provide protection against respiratory pathogens and inhaled toxins, but little is known about the early development of lung immune cells. Using single cell transcriptomics, Barnes et al. characterized human embryonic and fetal immune cells in the developing lungs between 5 and 22 weeks post-conception. All stages of B cell development were detected, including mature B-1-like cells, suggesting that fetal lungs provide a local niche for B cell maturation. Myeloid cells were widespread, including near epithelial tips, and produced IL-1β, which induced epithelial stem cell differentiation into basal cells within fetal lung organoids. Together, these findings provide an immune atlas of developing human lungs and suggest a role for fetal immune cells in guiding development of the lung epithelium.