Background: Membrane-bound CD14 (mCD14) is a myeloid differentiation antigen expressed on monocytes/macrophages and neutrophils. It is a key molecule responsible for the innate recognition of bacteria by host cells and functions as an important receptor for bacterial lipopolysaccharide. This study investigated the in vivo expression profile and levels of mCD14 in healthy and diseased gingival tissues.
Methods: Gingival biopsies were obtained from 24 patients with chronic periodontitis, including 22 periodontal pocket tissues, 13 clinically healthy tissues, and 18 inflamed connective tissues (i.e., granulation tissues). Gingival biopsies from seven periodontally healthy subjects were used as controls. mCD14 was detected by immunohistochemistry.
Results: mCD14 was detected in 21 of 22 periodontal pocket tissues and all other categories of tissues. The mCD14-positive cells were mainly confined to the gingival epithelium-connective tissue interface. The expression levels in periodontally healthy subjects were significantly higher than in the patients. Within the patients, clinically healthy tissues showed greater levels of mCD14 than periodontal pocket tissues and granulation tissues.
Conclusions: mCD14 was commonly expressed in both healthy and diseased gingival tissues and was predominantly confined to the epithelium-connective tissue interface. The positive relationship observed between mCD14 expression levels and periodontal health may imply that mCD14 is associated with favorable host responses to bacterial challenge and contributes to maintaining periodontal homeostasis.