Expression of EGF-receptors on epithelial and stromal cells of normal and inflamed gingiva.

Immunolocalization techniques were used to examine the expression of the cell surface receptors of EGF in normal and inflamed gingival tissue. Detectable levels of receptor were not observed in any (0/6) of the normal tissue biopsies examined; in contrast, the EGF-receptor was expressed by both epithelial and stromal cells in 7/9 of the inflamed tissue biopsies. Receptor expression by epithelial cells in inflamed tissues exhibited a variable distribution pattern. In the majority of sections, staining was confined to cells in the spinous, granular and cornified cell layers, with little in the basal layer. Occasionally, isolated islands of stained epithelial cells were present, suggesting their clonal origin. Staining for the EGF receptor was also observed in fibroblasts and endothelial cells throughout the lamina propria of inflamed tissue. Positive staining for the receptor ligand (EGF) was observed in both normal and inflamed tissue. These data suggest that an up-regulation of cell surface receptors for EGF occurs during the inflammatory response, this resulting in an increased cellular responsiveness to EGF.