Differential expression of Class II (DR & DQ) antigens by human gingival Langerhans' cells and keratinocytes in vitro.

The expression of the Class II products DR and DQ on human gingival epithelium was examined using immunofluorescence and immunoperoxidase staining. Differential expression of Class II antigens was seen in chronic gingivitis in adults, with T6(+) DR(+) cells being more numerous than T6(+) DQ(+) cells. The periodontopathic organism Fusobacterium nucleatum (FN) induced DQ expression on Langerhans' cells (LC) during in vitro explant culture of gingival tissue. This effect was mimicked by endotoxin (LPS) from F. nucleatum and by E. coli LPS. These results indicate that differential expression of Class II products, a feature of chronic gingival inflammation, may result from the action of LPS on gingival LC.