The OX-2 membrane glycoprotein, also known as CD200, contains two IgSF immunoglobulin domains, a transmembrane region, and a cytoplasmic domain that is 19 amino acids long. CD200 belongs to the immunoglobulin superfamily, specifically within the B7 receptor family.CD200R1 is the cell surface transmembrane glycoprotein CD200 receptor 1, expressed on bone marrow cells and CD4+ T cells.Binding of CD200 to CD200R leads to tyrosine phosphorylation on the CD200R cytoplasmic PTB domain. This results in recruitment of adaptor proteins DOK-1 and DOK-2, facilitating the binding of SHIP with DOK-1, as well as recruitment of RasGAP, thereby negatively regulating the MAPK/ERK signaling pathway. This signaling cascade leads to inhibition of pro-inflammatory cytokine release, suppression of immune cell activation, and inhibition of mast cell degranulation.The CD200R1 Blockade Reporter Cell Line reporter gene cell line replaces the intracellular inhibitory signal of the CD200R1 protein with a strong activating signal. When CD200 binds to the surface-modified CD200R1 protein, activation occurs in the intracellular region of CD200R1, subsequently activating downstream signaling pathways to induce expression of luciferase. This activation can be blocked by antibodies with a blocking effect. Luciferase readings indicate the activation and blocking effects of the signaling pathway, making it useful for evaluating the in vitro effects of CD200 and CD200R1-related antibody drugs.
