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Updated: May 26, 2026

Isolation and In Vitro Culture of Murine and Human Alveolar Macrophages
Published on: April 20, 2018
Alveolar macrophages undergo postnatal transition from a hyperphagocytic and proinflammatory profile to a tolerogenic
Hang Yu1,2, Shengwen Shang2,3, Qing Xu2,4
1Center for Xin'an Medicine and Modernization of Traditional Chinese Medicine of IHM, The First Affiliated Hospital of Anhui University of Chinese Medicine, Hefei, Anhui 230031, China.
Abstract:
Alveolar macrophages (AMs) are crucial for lung immunity and homeostasis. While the ontogeny of AMs is well characterized, their postnatal phenotypic and functional maturation remains unclear. Here, we developed a bronchoalveolar lavage (BAL) protocol across key developmental stages and systematically analyzed age-dependent changes in AMs. AM numbers increased with age, acquiring a mature phenotype alongside alveolar maturation. BAL-recovered AMs decreased in size and increased in roundness from day 3 onward and revealed distinct gene expression profiles across different ages. Functionally, phagocytic capacity peaked in 3-day-old mice. Furthermore, AMs from day 1 showed higher basal inflammatory cytokine expression and an elevated response to LPS, indicating that the postnatal transition from a proinflammatory profile to a tolerogenic profile underscores the intrinsic adaptation of AMs to the immunotolerant microenvironment of the mature lung. Our study provides a useful protocol for mouse AM isolation and a comprehensive kinetic profile of postnatal AM development.
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