A variety of techniques have been directed toward the isolation and study of blood group antibodies. These include low-temperature ethanol (Cohn) fractionation, electrophoresis, ultracentrifugation and column chromatography on ion exchange celluloses. Modifications of the last technique have been applied by several groups of investigators. Abelson and Rawson, using a stepwise elution scheme, fractionated whole sera containing ABO and Rh antibodies on diethylaminoethyl DEAE cellulose and carboxymethyl cellulose. Speer and coworkers, in a similar study of blood group antibodies of whole sera, used a series of gradients for elution from DEAE-cellulose. Fahey and Morrison used a single, continuous gradient at constant pH for the fractionation of anti -- A and anti -- B agglutinins from preisolated | g-globulin samples.

In the present work whole sera have been fractionated by chromatography on DEAE-cellulose using single gradients similar to those described by Sober and Peterson, and certain chemical and serological properties of the fractions containing antibodies of the ABO and Rh systems have been described.

Serum samples were obtained from normal group A, group B and group O donors. Three of the anti -- Rh sera used were taken from recently sensitized individuals. One contained complete antibody and had a titer of 1: 512 in saline. The second contained incomplete antibody and showed titers of 1: 256 in albumin and 1: 2048 by the indirect Coombs test. The third, containing the mixed type of complete and incomplete antibodies, had titers of 1: 256 in saline, 1: 512 in albumin and 1: 1024 by the indirect Coombs test. In addition one serum was obtained from a donor (R. E..) who had been sensitized 6 years previously. This serum exhibited titers of 1: 16 in albumin and 1: 256 by the indirect Coombs test. These antibody titers were determined by reaction with homozygous ** f red cells.