Enhancement of amyloid induction by amyloid fibril fragments in hamster.

An extract (fibril amyloid-enhancing factor) prepared by sonication of a suspension of water-purified hamster AA-amyloid fibrils showed an amyloid-enhancing effect upon intraperitoneal injection into hamsters. The fibril amyloid-enhancing factor was identical to the original fibrils according to the results of infrared spectroscopy, gel filtration, gel electrophoresis, and Western blotting; although lyophilized samples of the extract did not show any green birefringence after staining with Congo red. From these results, it was concluded that fibril amyloid-enhancing factor represents small fragments of amyloid fibrils which enhance in vivo formation of amyloid fibrils.