CD200R1 (Cluster of Differentiation 200 Receptor 1): CD200R1 is a member of the immunoglobulin superfamily that serves as a key regulator of immune responses and cellular interactions. This receptor is primarily expressed on various immune cells, including macrophages, dendritic cells, and B cells. Its main ligand, CD200, is present on a wide range of cell types and functions as a suppressive signal to modulate immune activity. The interaction between CD200R1 and CD200 activates inhibitory signalling pathways that suppress inflammatory responses and promote immune tolerance. Additionally, CD200R1 signalling plays an important role in maintaining immune homeostasis and preventing excessive immune activation.