Lectin binding of rat gingival epithelia.

Oral gingival epithelium (OGE), oral sulcular epithelium (OSE) and junctional epithelium (JE) were examined histochemically by using different lectins as markers for epithelial differentiation. The staining pattern of gingival epithelia was compared with that of the buccal and palatal epithelia. Binding of WGA had a uniform distribution in all the epithelia examined. A positive reaction was found in all the basal and spinous layers, but not in the cornified layer of the epithelia. BPA binding was seen in the lower spinous layer of OGE, OSE, buccal and palatal epithelia, and in most of the JE. The basal layer and the cells directly attached to the tooth surface at the apical part of JE were nonreactive with BPA. GS-I reacted with the basal and suprabasal layers of each epithelium and with the cells attached to the tooth at the apical part of JE. UEA-I reacted with the upper spinous layer of OGE, OSE and epithelia of hard palate, but not with any of the cells of the JE. Our results agree with previous data suggesting that OGE and OSE exhibit squamous differentiation similar to that of the masticatory epithelium of hard palate. Furthermore, our results suggested that the JE cells undergo differentiation equivalent to that of the suprabasal and lower spinous cells of OGE. The cells along the tooth surface at the apical part of JE, however, form a distinct population of cells with basal nature.