Degradation of endogenous plasma membrane fibronectin concomitant with Treponema denticola 35405 adhesion to gingival fibroblasts.

Treponema denticola adhesion and degradation of fibronectin (Fn) on human gingival fibroblasts (HGF) were studied by immunofluorescence and enzyme-linked immunosorbent assays. The number of adherent bacteria increased and the amount of immunoreactive Fn decreased as a function of increasing T. denticola concentration. The distribution of cell-bound Fn was punctate in micrographs. Anti-human Fn impaired bacterial adhesion to HGF. Phenylmethylsulfonyl fluoride inhibited Fn degradation but not adhesion. Sonicated extracts and diluted spent growth medium degraded HGF Fn but, unlike intact T. denticola cells, they hardly stimulated F-actin rearrangements.