An Immunological and Electrophoretic Comparison of the Antibody to C Polysaccharide and the C-reactive Protein of Acute Phase Serum

1. Studies of the precipitation reaction of C polysaccharide with C protein, and of C polysaccharide with C antibody are reported. The similarity between these two systems in this respect is demonstrated. 2. The differences between C protein and C antibody are emphasized. The differences between this protein and antibodies in general have been reported previously by others. 3. Electrophoretic studies show that C antibody is in the gamma globulin fraction of serum whereas C protein migrates with the alpha(1) globulin fraction of acute phase protein.