Identification and isolation of five developmental stages in GM-CSF-stimulated murine bone marrow culture.

Abstract

Dendritic cells (DCs) are highly potent cells that link the innate immunity with the adaptive. However, these cell types (and their precursors) are extremely rare in vivo. Considerable work has been done to map the development and function of DCs that develop in the absence of inflammation. However, due to their conditional development and short life-span, our understanding of the development and function of inflammatory-derived DCs is lacking. DCs generated from granulocyte/macrophage-colony stimulating factor (GM-CSF) stimulated murine bone marrow have been used for nearly half a century as a model for studying DC functions. However, recent studies have shown these cells to be considerably more heterogenous than previously believed. In studying this heterogeneity, we found five developmentally distinct populations that could be identified and isolated based on expression of three cell surface molecules: Ly6C, CD115 (CSF-1R), and CD11c. We further characterized these populations based on gene expression profiles, cell surface marker expression, and response to molecules which can initiate an immune response. These characterizations suggest the five identified populations correspond to five discreet developmental stages identified in vivo: Common Myeloid Progenitors (CMP), Granulocyte/Macrophage Progenitors (GMP), Monocytes, Monocyte-derived macrophages (moMac), and Monocyte-derived DC (moDC). Furthermore, we have identified a subset of moMacs which possess the capacity to give rise to moDCs, thus termed moDC precursors (moDP).