Characteristics of the binding of streptococcal lipoteichoic acid to human oral epithelial cells.

Membrane receptors for lipoteichoic acid (LTA) may be involved in the adherence of streptococci to human pharyngeal epithelial cells. Since streptococcal binding to oral epithelial cells has been shown to be low at birth with a gradual increase to adult levels within three days, the characteristics of the binding of radiolabeled LTA to epithelial cells were investigated. LTA binding to epithelial cells from both infants and adults was time- and cell concentration-dependent. Binding was reversible in the presence of a 50-fold excess of unlabeled LTA. The number of LTA-binding sites in infant cells was only one-half that of adult cells; the amount of LTA bound increased to adult levels within three days of birth and paralleled an increase in the ability of these cells to bind streptococci. Thus, oral epithelial cells may possess specific binding sites for LTA, and a critical number or arrangement of LTA-binding sites may be required for the optimal binding of streptococci.