Immuno-ultracentrifugation: a combination of density gradient centrifugation and immunodiffusion

By incorporating acrylamide in a sucrose gradient and photopolymerizing the tubes at the end of the run, direct immunochemical and other analysis can be performed on the separated material in situ without recovering fractions from the centrifuge tube. Immunodiffusion performed on the sliced gel can be employed to locate antibody activity in the gel slice or determine the distribution of antigens in a sucrose gradient