Contrasting responses of human gingival and colonic epithelial cells to lipopolysaccharides, lipoteichoic acids and peptidoglycans in the presence ofsoluble CD14

Gingival epithelial cells may form the first barriers of defense against or al bacteria in periodontal tissues. We stimulated human gingival epithelial cells (keratinocytes) in primary culture, the oral epithelial cell line KB and the colonic epithelial cell line SW620 with various bacterial cell-sur face components in the presence or absence of soluble CD14 (sCD14). The SW6 20 produced interlukin-8 (IL-8) in an sCD14-dependent manner in response to lipopolysaccharide, lipoteichoic acid and peptidoglycan. However, the prim ary gingival epithelial cells and KB cells did not show enhanced production of IL-8 upon stimulation with these components even in the presence of ser um. These human epithelial cells were devoid of membrane CD14, as determine d by flow cytometry, and CD14 mRNA expression, as determined by reverse tra nscriptase-PCR. In contrast, gingival epithelial cells and KB cells express ed the mRNA expression for Toll-like receptor (TLR) 2, TLR4, MD2 and MyD88 to the similar extent to those observed in SW620 cells.