Chemical and serological characteristics of blood group antibodies in the ABO and Rh systems

By means of chromatography on DEAE-cellulose utilizing elution with single, continuous gradients, blood group antibodies of the ABO system were separated into at least three regions, having extremely low, low, and high anionic binding capacities, respectively. This was true whether whole serum or Cohn Fraction II + III was chromatographed. Activity in the first region was associated with 6.6 S γ2-globulins; that in the second, with 6.6 S γ1-globulins; that in the third, with γ1-globulins of high sedimentation coefficient (probably 17.5 S, uncorrected) and a molecular weight of the order of 700,000. In all sera studied, most of the activity lay in the third region. This was particularly noticeable in group A and group B sera, in which activity in the first two regions was usually not detectable without prior concentration. This technique failed to separate the anti-A and anti-B activities of group O serum. Chromatography of whole sera showed that incomplete Rh antibodies were associated with 6.6 S γ-globulins of low anionic binding capacity, whereas complete Rh antibodies were associated with γ-globulins of high anionic binding capacity and (presumably) high molecular weight. Serum containing both types of antibodies exhibited activity in both chromatographic regions. In all cases, the active regions were wider when tested with homozygous R̄h0(-D-) cells than when tested with homozygous Rh0(D) cells.