Collectin-11 (CL-11)

Collectin-11 (CL-11), also known as alias collectin kidney 1 (CL-K1) is a recently identified member of collectins, encoded by COLEC11. It is produced by several types of non-immune cells, including epithelial cells of the renal tract and mucosal cells in the intestinal and bronchial tracts. CL-11 has a classical collectin structure containing an N-terminal segment, a collagen-like region, an alpha-helical coiled neck region, and a C-terminal carbohydrate recognition domain (CRD) which is responsible for the recognition of multiple sugars with a preference for fucose and mannose. Similar to other collectins, CL-11 plays an important role in innate immunity through binding to carbohydrate antigens on microorganisms and activating complement through the recruitment of mannose-binding lectin (MBL)-associated serine proteases (MASPs). Also, CL-11 has been shown to play a role in apoptosis through binding to the DNA present at the surface of apoptotic cells in a calcium-independent manner and activating the complement in response to this binding. Interestingly, CL-11 is also involved in the development via guiding the migration of neural crest cells and other cell types during embryogenesis.

CL-11 plays a crucial role in innate defense against invading microorganisms. It has been revealed to play a protective role in uropathogenic Escherichia coli (UPEC)-induced urinary tract infection (UTI) through inducing innate immunity defense. Besides, CL-11 is also involved in the pathogenic progress of several diseases. It has been also shown to be associated with acute kidney injury (AKI) through recognizing an abnormal pattern of L-fucose on postischemic renal tubule cells and activating a destructive inflammatory response. Deficiencies of CL-11 are associated with 3MC syndrome-2 and Chagas disease.

Fig.1 Hypothesis of local complement activation triggered by CL-11 on stressed epithelial cells. (Nauser, 2018)

Reference

1. Nauser, C.L.; et al. Collectin-11 (CL-11) Is a Major Sentinel at Epithelial Surfaces and Key Pattern Recognition Molecule in Complement-Mediated Ischaemic Injury. Front. Immunol. 2018.