Fibrin degradation products in growth stimulatory extracts of pathological lesions.

We have previously shown that similar patterns of fibrin degradation products (FbDP) by gel electrophoresis and immunoblotting are present in extracts of human atherosclerotic plaques, human and experimental wounds and breast cancers. Such extracts were also shown to stimulate cell proliferation including angiogenesis in the chick chorioallantoic membrane, now shown also for breast cancers. Removal of FbDP from plaque extracts by an anti-fibrinogen affinity column, or by an anti-fragment E column, reduced activity. Human FbDP prepared in vitro were active, but not FgDP. Fibrin fragment E was active, and we also showed that admixture of FbDP with a polyclonal rabbit anti-fibrin E but not anti-fibrin D neutralized activity. However attempts to raise comparable monoclonal blocking antibodies were hindered by species similarities. The response of the Balb/c mouse was predominantly directed at minor D contaminants, in contrast to the Sprague-Dawley rat which responded to fibrin fragment E in our antigen preparation.