A monoclonal antibody recognizing apolipoprotein E peptides in systemic amyloid deposits.

A monoclonal antibody was produced by immunization of mice with a crude amyloid A (AA) fibril preparation. This antibody (YK-2), when used in immunohistochemical studies, showed positive staining of amyloid deposits in tissues from patients with systemic amyloidosis (three idiopathic, three myeloma-associated, five reactive, one familial amyloid polyneuropathy, and three dialysis-associated). Immunoblotting revealed that YK-2 reacted with 14,000 and 7,000 dalton components of AA fibrils and a 36,000 dalton component of normal human serum. Absorption with purified human apolipoprotein E abolished staining. This suggests that fragments of apolipoprotein E are a common constituent of amyloid fibril of diverse origins, and it can be a new marker for immunohistochemical studies of systemic amyloidosis.