Clostridial collagenase. A chemoattractant for human neutrophils

Leukocyte chemoattractants markedly alter the morphology and membrane functions of leukocytes. Bacterial collagenase causes a change in cell shape similar to that seen with the leukocyte chemoattractant, f-Met-Leu-Phe, and also promotes capping of concanavalin A. Human neutrophils in suspension or adherent to cover glasses were exposed to clostridial collagenase (10-250 units/ml) for up to 30 min at 37 degrees C and then fixed. Collagenase (125 units/ml) caused more than 85% of PMNs to assume an asymmetric or motile morphology even in the presence of 1% gelatin or 10 mg/ml bovine serum albumin. Trypsin alone (0.01-1%) did not induce a shape change. A similar morphology was seen in some untreated PMNs (less than 5% of all cells) and is characteristic of f-Met-Leu-Phe-treated cells (more than 90%). Collagenase inhibitors (i.e., reduced glutathione, cysteine, and acid-soluble collagen), however, prevented the shape change induced by collagenase but not by f-Met-Leu-Phe. At 4 degrees C, fluorescein-Con A (20 micrograms/ml) bound uniformly to both untreated and collagenase-treated cells. Upon further incubation at 37 degrees C, Con A was internalized over the entire cell periphery of the rounded, untreated cells but on collagenase-treated PMNs was rapidly gathered into a cap overlying the uropod or protuberant region of cytoplasm where it was subsequently internalized. Checkerboard Boyden chamber assays showed clostridial collagenase to be chemokinetic and chemotactic for human PMNs. In receptor binding experiments, the clostridial collagenase preparation competed poorly with [125I]formylhexapeptide for binding to PMN formylpeptide receptors (less than 15% reduction in binding at 200 units/ml collagenase). Thus, collagenase does not seem to interact strongly with the neutrophil formylpeptide receptor and may stimulate PMN motility by interacting at an altogether different site.