Identity, ontogeny, and age-related changes in splenic white pulp macrophages in mouse and human spleen [XX_Mouse_GEO]

The mouse spleen hosts red pulp macrophages (RPM), marginal zone macrophages (MZM), marginal zone metallophilic macrophages (MMM), and tingible body macrophages (TBM). However, their transcriptomic identity, ontogeny, and dynamics during aging are unknown.

Furthermore, it is not known whether homologous populations of macrophages exist in the human spleen. We find that in mice, MZM and MMM are tissue-resident macrophages that maintain their population via local proliferation, while TBM are slowly replaced by circulating monocytes. Lineage tracing shows that MMM maintain the MZM pool, and that after MMM depletion, circulating monocytes restore MMM.