A novel type of antigen presenting cells in mouse

The mononuclear phagocyte system (MPS), composed of monocytes/macrophages and dendritic cells (DCs), plays a critical role at the interface of the innate and adaptive immune systems. However, the simplicity of the components of MPS has been challenged recently. In the present study, we identified and characterized the CD135+ subset of monocytes as a novel class of antigen-presenting cells (APCs) in mouse. We analyzed the comprehensive gene expression profiles of these populations and known populations in the MPS by RNA-Seq to define their hierarchical and relative position in the MPS. These findings facilitate our understanding of the MPS network that regulates immune responses for host defense.