The Separation by Starch Electrophoresis of Two Antibodies to Sheep Red Cells DIffering in Hemolytic Efficiency

Starch electrophoresis of eight rabbit antiserums resulted in the separation of two Forssman and two isophile antibodies which differed in electrophoretic and hemolytic properties. In one Forssman antiserum and in three anti-Forssman globulin preparations, a single peak of hemolytic activity was found between the β and γ₁ globulin or "T-component"), whereas peak combining capacity was found in the more slowly migrating globulin (γ₂ globulin). In most cases the hemolytic efficiency of the γ₁ fraction was approximately 100 times that of the γ₂ fraction. With two Forssman antiserums which possessed initially a low ratio of hemolytic to combining capacity, a second hemolytic peak which paralleled the peak of combining capacity was found in the γ₂ fraction. In three isophile antiserums and in one anti-isophile globulin preparation, peak hemolytic activity was found in the γ globulin fraction coinciding with the peak of the protein curve. Peak combining capacity was found in the γ₂ fraction. The hemolytic efficiency of the more rapidly migrating fraction was about 50 times greater than that of the γ₂ fraction. No differences between intact and splenectomized rabbits were found in the electrophoretic distribution of the two Forssman antibodies.