Macrophage mannose receptor (MMR) or CD206 is an endocytic and phagocytic receptor that recognizes appropriately configured carbohydrate ligands in target molecules.
CD206 is expressed mainly in mature tissue macrophages and immature dendritic cells, and is thought to play a role in both the innate and adaptive immune responses of the host. The expression of CD206 is affected, among other factors, by pathogens, cytokines and immunoglobulin receptors.
While the protein sequence information predicts CD206 to weigh around 166kDa, the cleavage of the signal peptide gives rise to an immature 154 kDa protein before undergoing N- and O-linked glycosylation to result in a 162 kDa mature molecule in macrophages. Secreted forms resulting from the proteolytic cleavage of the extracellular domain have also been observed. The binding to mannose is calcium dependent.