Hu CD200, 100 _g

Cluster of differentiation 200 (CD200), also known as OX-2, is a type 1 membrane glycoprotein belonging to the immunoglobulin superfamily, expressed with a polyhistidine tag at the C-terminus (Accession NP_005935.4, Gln31–Gly232). The protein contains two immunoglobulin-like domains — a V-type domain and a smaller C2-type domain — and interacts with the CD200 receptor (CD200R), which is expressed on the surface of myeloid cells and T cells. In vitro studies indicate that CD200–CD200R interaction inhibits myeloid cell activity and macrophage cytokine production, while viral homologues of CD200 can engage CD200R to reduce macrophage pro-inflammatory cytokine output. The immunosuppressive properties of CD200 have been associated with promotion of allogeneic tissue graft acceptance in hosts, and dysregulation of the CD200/CD200R axis has been implicated in autoimmune conditions such as rheumatoid arthritis.

From STEMCELL Technologies, this human recombinant CD200 is produced in HEK293 cells and supplied lyophilized from sterile PBS (pH 7.4) with trehalose (5%), mannitol (5%), and 0.01% TWEEN 80 as protectants. The protein has a predicted molecular mass of 24 kDa and an apparent molecular mass of 40–45 kDa due to glycosylation, with a purity of ≥ 90%. In a functional ELISA, the immobilized protein at 2 μg/mL binds human CD200R (His & hFc tag) with a linear range of 5–28 ng/mL, and the endotoxin level is ≤ 1 EU/μg protein. The lyophilized product should be stored at -20 to -80°C and is stable as supplied for 12 months from the date of receipt. To prepare, the vial should be centrifuged before opening and the contents reconstituted in sterile water to at least 0.25 mg/mL by pipetting the solution down the sides of the vial; vortexing should be avoided. For research use only.