Mannose receptor (CD206) (CD206)

The mannose receptor (CD206), also known as MRC1, is a type I transmembrane C-type lectin receptor predominantly expressed on macrophages, dendritic cells, and liver sinusoidal endothelial cells. It features an N-terminal cysteine-rich domain for sulfated sugars, a fibronectin type II domain for collagen binding, and eight carbohydrate recognition domains (primarily CRD4-5) that recognize terminal mannose, fucose, or N-acetylglucosamine on pathogens and glycoproteins, facilitating clathrin-mediated endocytosis, phagocytosis, and clearance of waste glycoproteins to maintain immune homeostasis. In disease, CD206 marks M2-polarized tumor-associated macrophages in cancer, contributes to granuloma formation in tuberculosis, and drives metabolic dysfunction in obesity by promoting inflammatory macrophages that induce insulin resistance. It plays dual roles in immunity: aiding pathogen uptake and antigen presentation for adaptive responses while also inducing T cell tolerance via CD45 inhibition, potentially limiting anti-tumor cytotoxicity. Therapeutically, CD206 is exploited for targeted delivery using mannosylated nanoparticles or nanobodies to enhance macrophage uptake of anti-TB drugs, siRNA, vaccines, and oligonucleotides, bypassing direct agonists due to its endocytic nature. Expression is low during inflammation but rises during resolution, highlighting its regulatory function.

Other names

macrophage mannose receptorMRC1mannose receptor C type 1

receptor-mediated endocytosis and uptake of mannosylated carriers for drug/siRNA delivery into macrophages; clathrin-dependent internalization