Cellular location of a Treponema denticola chymotrypsinlike protease and importance of the protease in migration through the basement membrane.

A number of immunological methods were used to localize a cell-associated Treponema denticola chymotrypsinlike protease. Indirect immunofluorescence staining, immunogold labeling, and an enzyme-linked immunosorbent assay all indicated that the protease was attached to the outside of the cell envelope. The invasive capability of T. denticola was evaluated by following the degradation of a reconstituted basement membrane material (Matrigel) and the release of spirochetes from the gel. Under conditions where the chymotrypsinlike activity was increased, more spirochetes migrated from the gel. Protease inhibitors strongly reduced the number of cells that moved out of the gel. The purified chymotrypsinlike protease degraded the basement membrane components type IV collagen, laminin, and fibronectin. The study suggests that the T. denticola chymotrypsinlike protease may play an important role in the invasion and destruction of basement membrane.