Development and comparison of purification strategies for chicken antibodies from egg yolk

With regard for animal welfare as well as cost, antibodies purified from the egg yolk of immunized chickens are an attractive alternative to antibodies raised in serum of mammals. Various purification strategies based on initial purification by a freeze-and-thaw method followed by one of three precipitation methods--ammonium sulfate, polyethylene glycol 6000, or caprylic acid--were compared. Ammonium sulfate precipitation (25 to 40%) was found to give the best combination of high purity and yield (58%). Moreover, this method is inexpensive and well suited for standard purification of egg yolk antibodies in large scale production facilities.