Protocol for detection of autoantibodies with self-assembling radiolabeled antigen tetramers. Details how to produce radiolabeled antigen-streptavidin tetramers for detection of antibodies by immunoprecipitation. Optionally, the antigen tetramers can be denatured to compare responses to folded and unfolded antigen in the same system. This technique can be applied to a large or small number of samples, and a given sample can be simultaneously assayed with multiple antigens. - [Read Detection of Autoantibodies with Self-Assembling Radiolabeled Antigen Tetramers Protocol]