Characterization of antibodies to basement membrane (type IV) collagen in immunohistological studies.

Antisera were produced in rabbits and guinea pigs against basement membrane (type IV) collagens which were extracted from a mouse tumor with acetic acid and from human placenta after limited digestion with pepsin. The antisera were specific for type IV collagen and did not crossreact with collagens type I, II and III from interstitial connective tissue, with collagen type V (AB2) from placenta and with a non-collagenous protein (laminin) obtained from basement membranes. Purified antibodies against both human and type IV collagen reacted in indirect immunofluorescence tests with the mouse tumor matrix and with authentic basement membranes in various human and mouse tissues. These antibodies failed to react with interstitial connective tissue. Absorption of antibodies against type IV tumor collagen with mouse or human kidney homogenate abolished or significantly decreased their reaction with tumor tissue. The findings indicate that various basement membranes may contain related or identical collagenous proteins which show a high degree of interspecies homology.