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. CD200 and CD200R1 interact via their respective N-terminal Ig-like domains. Expressed in granulocytes, monocytes, most T-cells and a subset of NK, NKT and B-cells (at protein level). Expressed in the spleen, lung, liver, testis, bone marrow, lymph nodes, spinal cord, kidney, uterus and small intestine. Expressed in mast and dendritic cells. Expressed in the lung of N. brasiliensis-infected mice. Belongs to the CD200R family. May be expressed in adult splenic cells (PubMed:15187158), as the antibody used could not discriminate between CD200R1 and CD200R4. May be expressed in uterus at 12.5 dpc (at protein level) (PubMed:15274657), as the antibody used could not discriminate between CD200R1 and CD200R4.