Research ArticleMACROPHAGES

CD169+ macrophages orchestrate innate immune responses by regulating bacterial localization in the spleen

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Science Immunology  06 Oct 2017:
Vol. 2, Issue 16, eaah5520
DOI: 10.1126/sciimmunol.aah5520

Positioning sentinels

Immune cells in the marginal zone of the spleen, particularly marginal zone macrophages, play a critical role in detecting and capturing blood-borne pathogens. Here, Perez et al. have examined the role of CD169+ splenic marginal zone macrophages in priming antibacterial responses. Selective deletion of CD169+ macrophages using a diphtheria toxin–based depletion system severely impaired the ability of mice to clear Listeria monocytogenes. By tracking L. monocytogenes and immune cells, they show that CD169+ macrophages cooperate with splenic dendritic cells to transport bacteria from the marginal zone to the T cell zone to prime immune responses to Listeria. The study illustrates the importance of splenic architecture in containing initial pathogen dissemination and in shaping antimicrobial responses.