Partial Purification of Alzheimer’s Amyloid-𝛽 Specific Antibody Using Ammonium Sulfate

Alzheimer's disease (AD) is the most common neurodegenerative disease. The trigger for AD is the accumulation of amyloid-beta protein (Aβ) as senile plaques in the brain. Prior to forming the fiber-like structures found in the plaques, Aβ undergoes an oligomerization process that produces intermediate structures called protofibrils. Substantial data from the Nichols laboratory demonstrated that soluble Aβ protofibrils were highly inflammatory compared to other forms of Aβ. Based on these findings, a serum polyclonal antibody, named Antibody St. Louis or AbSL, was developed to target Aβ protofibrils. A significant challenge with serum antibodies is the presence of many other biological factors in the samples. This study investigates the application of ammonium sulfate (AS) to precipitate and partially purify the AbSL antibody from serum, aiming to enhance its sensitivity and specificity. Two separate purification experiments indicated that the serum AbSL antibody could be precipitated between 20% and 50% AS. The AbSL antibody was tracked in different fractions using an ELISA assay. Further studies will help determine the exact solution that will give optimal purification of the AbSL serum antibody. This method will effectively eliminate extraneous serum proteins that could potentially impede the functionality of the antibody.