Clone REA812 recognizes the human CD163 antigen, a single-chain transmembrane protein also known as hemoglobin scavenger receptor or M130. It is expressed by mature tissue macrophages and peripheral blood monocytes. The expression of CD163 is up-regulated in vitro
and in vivo
by anti-inflammatory mediators such as interleukin 10 (IL-10) and (gluco)corticosteroid and is shed to blood upon inflammatory activation of macrophages. CD163 functions as a high affinity scavenger receptor for the complex of haemoglobin and haptoglobin. Depending on the ligand, crosslinking of CD163 initiates signal transduction leading to the production of proinflammatory cytokines Il-1ß, IL-6, and GM-CSF or the anti-inflammatory cytokine IL-10.