Localization of fibronectin in gingival connective tissue of the beagle dog. Immunofluorescent light microscopic findings.

Affinity purified antibodies to plasma fibronectin were used to localize fibronectin in the connective tissues of inflamed and noninflamed beagle gingiva. In noninfiltrated gingival connective tissue, fibronectin was demonstrated in the basement membrane beneath gingival epithelium and around blood vessels as a uniform and intensely stained band about 3 to 10 micron thick. Fibronectin was also distributed throughout the connective tissue in association with collagen fibrils as a more diffuse, less intensely stained pattern. The inflamed gingiva included in this study was characterized by proliferation of epithelial pegs, heavy infiltration of plasma cells and loss of collagen within the subepithelial connective tissue. In these sites, fibronectin was present as an intensely stained band around blood vessels and at the crest of connective tissue papillae nearest the sulcular space. The fibronectin in the basement membrane beneath the epithelium appeared diminished and less uniformly distributed. A delicate network of fibronectin was present around plasma cells and the remaining collagen fibers.