CD177

CD177 (the acronym CD stands for "Cluster of Differentiation" and refers to groups of cellular surface features that have been classified according to biochemical or functional criteria. The CD classification enables comprehensible transparency in immunohistological and immunological diagnostics).

CD177 is a cell surface protein (glycosylphosphatidylinositol (GPI)-anchored protein) that is expressed by a proportion of human neutrophils and mediates the surface expression of the antineutrophil cytoplasmic antibody antigen proteinase 3.

CD177 is a specific marker for neutrophils and is also referred to as human neutrophil antigen 2a (HNA-2a) or NB1. However, it is not expressed on all neutrophils, but only on a subpopulation.

CD177 is mainly expressed on neutrophil granulocytes, but is also found on other cell types. It belongs to the Ly-6 superfamily and is a glycoprotein that is bound to the cell membrane. CD177 plays a role in the immune response, particularly in the migration of neutrophils and the binding of IgG.

Furthermore, CD177 is involved in the migration of neutrophils by regulating the activation of integrins and chemoreceptors. It can also mediate the binding of IgG and play a role in antibody-dependent cellular cytotoxicity (ADCC). CD177 associates with β2 integrins and recognizes platelet endothelial cell adhesion molecule 1 (PECAM-1), also suggesting its role in neutrophil migration. However, CD177pos neutrophils show no clear migratory advantage in vivo, although transendothelial migration was disrupted in vitro by CD177 ligation.

Autoimmune diseases: CD177 is associated with autoimmune diseases such as granulomatosis with polyangiitis (GPA), where CD177-positive neutrophils are increased in the affected tissues.

IBD (Inflammatory Bowel Disease) During the development and progression of mucosal inflammation in IBD, most neutrophils specifically express CD177. CD177 promotes their migration. CD177+ neutrophils activate bactericidal and barrier-protective functions at IBD mucosal sites of inflammation and regulate the release of inflammatory mediators that are highly correlated with the severity of inflammation in IBD patients, thus playing a dual role.

CD177 and NETs: Neutrophils expressing CD177 have been found to play an important role in bile duct damage by releasing a specialized structure (NET) that can trap and kill pathogens, but can also cause severe tissue damage (Zhang R et al. 2022).

Tumors: CD177 can also be expressed in tumors, especially on tumor-infiltrating regulatory T cells (TI-Treg cells), and may play a role in immunosuppression.

Genetic variants: There are genetic variants of CD177 that may influence the expression and function of the protein, which may affect the immune response.

1. Bai M et al. (2017) CD177 modulates human neutrophil migration through activation-mediated integrin and chemoreceptor regulation. Blood130:2092-2100.
2. Zhang R et al. (2022) CD177+ cells produce neutrophil extracellular traps that promote biliary atresia. J Hepatol 77:1299-1310.
3. Zheng C et al. (2024) Dual role of CD177 + neutrophils in inflammatory bowel disease: a review. J Transl Med 22:813.