CD200

CD200 Full Name

Cd200 molecule

CD200 Introduction

OX-2 membrane glycoprotein, commonly referred to as CD200, is a type I membrane glycoprotein that belongs to the immunoglobulin superfamily (IgSF). Structurally, it consists of two extracellular immunoglobulin-like domains—an N-terminal variable (V)-type domain and a membrane-proximal constant (C2)-type domain—followed by a transmembrane region and a short cytoplasmic tail. CD200 is widely expressed across a diverse range of cell types, including B cells, activated T cells, neurons, vascular endothelial cells, and reproductive tissues. Its broad distribution suggests it plays a fundamental role in maintaining cellular communication and tissue integrity across the body.

Figure 1. Strcuture of CD200.

Signaling Mechanism and Biological Consequence
The immunosuppressive signal is mediated through the engagement of CD200 with CD200R. The cytoplasmic tail of CD200R contains tyrosine residues that, upon phosphorylation, recruit adaptor proteins such as DOK1 and DOK2. This recruitment leads to the activation of downstream effectors, including RASGAP and SHIP1, which ultimately inhibit MAPK and PI3K signaling pathways. The net biological effect is the suppression of pro-inflammatory cytokine production (e.g., TNF-α, IL-6), reduced oxidative burst, and an overall shift in myeloid cells toward a more tolerogenic or M2-like phenotype. This mechanism is crucial for controlling inflammation in sensitive environments like the central nervous system.

Conclusion
Given its pivotal role in regulating immune activity, CD200 has emerged as a significant target for therapeutic intervention. In oncology, researchers are developing humanized monoclonal antibodies (such as samalizumab) designed to block the interaction between CD200 and CD200R, thereby releasing the "brake" on the immune system and allowing it to recognize and destroy cancer cells. Conversely, in autoimmune diseases and transplant rejection, agonists that mimic CD200 activity are being explored to induce tolerance and reduce inflammation. This dual potential makes the CD200 pathway a cornerstone of current research in both cancer immunotherapy and autoimmune disease management.

Alternate Names for CD200

CD200; Cd200 molecule; Mox2; Cspmo2; MRCOX2; OX-2 membrane glycoprotein; Cd200 antigen; MRC OX-2 antigen; cell surface protein (thymocyte antigen identified by monoclonal antibody MRC-OX2);