Antibodies against senile plaque (SP) amyloid obtained a clone which labeled amyloid fibrils in SPs and reacted with approximately 50/100 kDa polypeptides in Alzheimer's disease (AD) brains. The antigen was identified as CLAC (collagen-like Alzheimer amyloid plaque component), and its precursor as CLAC-P/collagen type XXV. Both secreted and membrane-tethered forms of CLAC-P/collagen type XXV specifically bound to fibrillized Abeta, implicating these proteins in beta-amyloidogenesis and neuronal degeneration in AD.
