Abstract
Three Ficolins have been identified in humans: Ficolin-1 (M-Ficolin), Ficolin-2 (L-Ficolin), and Ficolin-3 (H-Ficolin). Ficolin-1 is the least-described of the Ficolins and is expressed by monocytes, granulocytes, and in the lungs. Ficolin-1 is found circulating at low concentrations in serum but is regarded primarily as a secretory molecule that exerts its function locally in inflamed tissues. Ficolin-1 has been reported on the surface of monocytes and granulocytes and was suggested originally to function as a phagocytic receptor. However, the molecule does not contain any obvious transmembrane domain, and no binding partners have been identified. To gain further insight in the physiological role of Ficolin-1, we sought to identify the molecular mechanism responsible for the membrane association of Ficolin-1 to monocytes and granulocytes. We demonstrate that expression of Ficolin-1 on the cell surface is restricted to monocytes and granulocytes. Ficolin-1 is tethered to the cell surface of these cells through its fibrinogen-like domain, and the ligand involved in the binding of Ficolin-1 is shown to be sialic acid. Moreover, rFicolin-1 bound activated but not resting T lymphocytes. Together, these results demonstrate a novel self-recognition mechanism of leukocytes mediated by the fibrinogen-like domain of Ficolin-1.
| Original language | English |
|---|---|
| Journal | Journal of Leukocyte Biology |
| Volume | 88 |
| Issue number | 1 |
| Pages (from-to) | 145-58 |
| Number of pages | 14 |
| ISSN | 0741-5400 |
| DOIs | |
| Publication status | Published - 1 Jul 2010 |