CD200 non-lytic Recombinant Protein

CD200, also known as OX-2, is a 45 kDa transmembrane immunoregulatory protein that belongs to the immunoglobulin superfamily. CD200 is widely but not ubiquitously expressed. Its receptor (CD200R) is restricted primarily to mast cells, basophils, macrophages, and dendritic cells, which suggests myeloid cell regulation as the major function of CD200. CD200 knockout mice are characterized by increased macrophage number and activation and are predisposed to autoimmune disorders. In T cells, CD200 functions as a costimulatory molecule independent of the CD28 pathway. Several viruses encode CD200 homologs which are expressed on infected cells during the lytic phase. Like CD200 itself, viral CD200 homologs also suppress myeloid cell activity, enabling increased viral propagation.