title: A stratified myeloid system, the challenge of understanding macrophage diversity.
abstract: The present issue of 'Seminars in Immunology' addresses the topic of macrophage biology, 100 years after the death of Elie Metchnikoff (May 1845-July 1916). As foreseen by Metchnikoff, the roles of macrophages in the maintenance of homeostasis and immunity against pathogens have become a broad and active area of investigation. We now start to realize that the myeloid system includes a multiplicity of cell types with diverse developmental origins and functions. Therefore, the textbook picture of a plastic and multifunctional macrophage does not meet the requirements of our current knowledge anymore. Further development toward a quantitative and molecular understanding of myeloid cell biology in vivo and their roles in tissue homeostasis and remodeling will benefit from taking this complexity into account. A tentative model to help in this pursuit and account for myeloid cell and macrophage diversity is discussed below.
authors.affiliation: Memorial Sloan Kettering Cancer Center, 417 E 68th St New York, NY 10065, USA; Weill Cornell Graduate School of Medical Sciences, Weill Cornell Medicine, 1300 York Avenue New York, NY 10065, USA. Electronic address: geissmaf@mskcc.org.
authors.forename: F
authors.initials: F
authors.lastname: Geissmann
authors.affiliation: Memorial Sloan Kettering Cancer Center, 417 E 68th St New York, NY 10065, USA; Weill Cornell Graduate School of Medical Sciences, Weill Cornell Medicine, 1300 York Avenue New York, NY 10065, USA.
authors.forename: E
authors.initials: E
authors.lastname: Mass
mesh_terms: D006801:Humans; D008264:Macrophages / Q000166:cytology* / Q000276:immunology; D008954:Models, Biological; D022423:Myeloid Cells / Q000166:cytology* / Q000276:immunology
keywords: Dendritic cells; Development; Differentiation; Immune response; Macrophage; Monocyte; Tissue remodelling