Inhibitory receptor for the CD200/OX2 cell surface glycoprotein. Limits inflammation by inhibiting the expression of pro-inflammatory molecules including TNF-alpha, interferons, and inducible nitric oxide synthase (iNOS) in response to selected stimuli. Also binds to HHV-8 K14 viral CD200 homolog with identical affinity and kinetics as the host CD200. CD200 and CD200R1 interact via their respective N-terminal Ig-like domains (By similarity). Interacts with Human herpesvirus 8 vOX2 protein. (Microbial infection) Interacts with human herpesvirus 8/HHV-8 protein vOX2/K14. Expressed in granulocytes, monocytes, most T-cells, neutrophils, basophils and a subset of NK, NKT and B-cells (at protein level). Expressed in bone marrow, lymph nodes, spleen, lung, liver, spinal cord, kidney. Expressed in monocyte-derived dendritic and mast cells. The mature form of isoform 2 and/or isoform 4 starts at sequence position 27 of the corresponding isoform. Belongs to the CD200R family.