Immunohistochemical Localization of Fibrinogen C Domain Containing 1 on Epithelial and Mucosal Surfaces in Human Tissues

J Histochem Cytochem. 2018 Feb;66(2):85-97. doi: 10.1369/0022155417743694. Epub 2017 Dec 8.


Fibrinogen C domain containing 1 (FIBCD1) is a transmembrane receptor that binds chitin and other acetylated compounds with high affinity. FIBCD1 has previously been shown to be present in the epithelium of the gastrointestinal tract. In the present study, we performed a detailed analysis of normally structured human tissues for the expression of FIBCD1 by quantitative PCR and immunohistochemistry. We find that FIBCD1 is expressed in epithelial cells derived from all three germ layers. Endodermal-derived epithelial cells throughout the gastrointestinal tract and the respiratory system showed high expression of FIBCD1 and also mesodermal-derived cells in the genitourinary system and ectodermal-derived epidermis and sebaceous glands cells expressed FIBCD1. In some columnar epithelial cells, for example, in the salivary gland and gall bladder, the FIBCD1 expression was clearly polarized with strong apical reaction, while other columnar cells, for example, in small and large intestine and in bronchi, the staining was equally strong apically and basolaterally. In keratinocytes in skin, tongue, and oral cavity, the FIBCD1 staining was granular. This expression pattern together with the known binding properties supports that FIBCD1 plays a role in innate immunity in the skin and at mucosal surfaces.

Keywords: FIBCD1; chitin; digestive system; fibrinogen-related domain; immunohistochemistry; innate immunity; mucosal immunity; pattern recognition; receptors; respiratory system.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Brain Chemistry
  • Epithelium / chemistry*
  • Epithelium / metabolism
  • Female
  • Gastrointestinal Tract / chemistry
  • Gastrointestinal Tract / metabolism
  • Gene Expression
  • Genitalia, Female / chemistry
  • Genitalia, Female / metabolism
  • Genitalia, Male / chemistry
  • Genitalia, Male / metabolism
  • HEK293 Cells
  • Humans
  • Immunohistochemistry
  • Male
  • Mucous Membrane / chemistry*
  • Mucous Membrane / metabolism
  • RNA, Messenger / analysis
  • RNA, Messenger / genetics
  • Receptors, Cell Surface / analysis*
  • Receptors, Cell Surface / genetics
  • Respiratory System / chemistry
  • Respiratory System / metabolism
  • Urinary Tract / chemistry
  • Urinary Tract / metabolism


  • FIBCD1 protein, human
  • RNA, Messenger
  • Receptors, Cell Surface