Development of a novel method for isolation of four developmentally distinct myeloid derived dendritic cells pre-cursors: phenotypic and functional analyses (HEM3P.283)

Abstract

Abstract Myeloid cell progenitors have the potential to give rise to dendritic cells which have a high capacity to stimulate adaptive immune responses as well as to cells with potent immunosuppressive activity. However, the stage in their development in which these functions are gained is poorly defined. Here, we developed a method for isolating progenitor populations at specific stages of development. Bone marrow cells were lineage depleted and cultured in GM-CSF to drive their differentiation toward a myeloid lineage for three days. Cells were then sorted based on Ly6C and CSF-1R (CD115) expression, two markers whose expression is known to change throughout myeloid ontogeny. We then monitored the developmental progression of each population based on the expression of these markers as well as other hallmarks of dendritic cell or myeloid suppressor cell phenotypes. We also measured the function of each population relative to antigen uptake and degradation as well as their response to stimulation by TLR agonists. Collectively, our results indicate that myeloid progenitors progress along this pathway: Ly6C-CD115- -> Ly6C+CD115- -> Ly6C+CD115+ -> Ly6C-CD115+ -> Ly6C-CD115+. Phenotypically, these populations represent CMP, MDSC, monocytes, immature DC, and more mature DC, respectively. These findings not only enhance our understanding of myeloid cell development and differentiation driven by GM-CSF, but also inform the design of GM-CSF-derived DC based vaccine strategies.