Gelatinase (type IV collagenase) immunolocalization in cells and tissues: use of an antiserum to rabbit bone gelatinase that identifies high and low Mr forms.

An antiserum was raised to rabbit bone gelatinase (type IV collagenase). It was shown by immunoblotting to detect both the low Mr (72,000) enzyme produced by connective tissue cells from rabbit, pig, human and mouse, as well as the high Mr (94,000-97,000) enzymes secreted by macrophages and polymorphonuclear leucocytes from these species, and by rabbit chondrocytes and endothelial cells. Crossed immunoblotting, antibody inhibition and deglycosylation studies indicated that the high and low Mr forms of gelatinase are immunologically distinct gene products, although their substrate specificity profiles are identical. The anti-gelatinase antiserum was used to immunolocalize the enzyme. Gelatinase was most efficiently detected in rabbit monocytes and connective tissue cells, but cells derived from the human and pig gave poor immunostaining, although mouse gelatinase stained well. The anti-gelatinase antiserum stained cells of the synovial tissue of rabbits at 14 days after induction of an antigen-induced arthritis, demonstrating its usefulness as a tool to assess the role of this enzyme in degradative events.