Rho(D) genotype and red cell Rho(D) antigen content

The Rh(o)(D) content of red cells obtained from different individuals as determined with I(181) anti-Rh(o)(D) showed a bimodal distribution. Family studies indicate that the cells with the lower antigen content represent the heterozygous Rh(o)(D) state and that the cells with 1.6 times more Rh(o)(D) correspond to the homozygous state.

A STUDY OF THE DISTRIBUTION OF INCOMPLETE RHESUS ANTIBODIES AMONG THE SERUM IMMUNOGLOBULIN FRACTIONS

Sera containing Rh antibodies were taken from Rh-negative women at intervals during pregnancy and postpartum. A selection of these was fractionated on DEAE cellulose and by density gradient ultracentrifugation. The distribution among the immunoglobulin fractions γ_SS, γ₁A, and γ₁M of Rh antibodies in the sera of Rh-negative women during pregnancy was analysed by these fractionation procedures and also by treatment with 2-mercaptoethanol and by testing with rabbit antisera prepared against purified immunoglobulin fractions. The experiments showed that incomplete Rh antibodies occurred in the 7_SS-, γ₁A-, and γ₁M-globulin fractions, although the bulk of the antibody was in the 7_SS. In addition, evidence that the previously described (13) "papain-type" antibody is an incomplete γ₁M-globulin is presented.

LOCALIZATION OF ANTIBODIES IN GROUP I AND GROUP II GAMMA-GLOBULINS

A wide assortment of antibodies has been analysed by qualitative and quantitative techniques for their content of group I- and group II-type γ-globulin molecules. These included Rh antibodies, isoagglutinins, thyroglobulin antibodies, dextran antibodies, and teichoic acid antibodies. All the antibodies studied showed the presence of both groups. However, the ratio of the two varied widely in different individuals and diverged markedly from the ratio in the total γ-globulin of the individual. Two antibodies isolated from the serum of the same individual showed different ratios for the two groups.

STRUCTURAL ASPECTS OF HUMAN ERYTHROCYTE AUTOANTIBODIES. I. L CHAIN TYPES AND ELECTROPHORETIC DISPERSION

The 7S gamma-globulins causing erythrocyte autosensitization in 20 patients were isolated by elution and examined for homogeneity or heterogeneity of their L chain types and electrophoretic dispersion. The isolated erythrocyte autoantibodies from 12 patients contained only 1 detectable L chain type. Two of these "monotypic" populations showed appreciable restriction of electrophoretic dispersion, while 2 others more nearly resembled the electrophoretic heterogeneity of normal gamma-globulins. The autoantibodies from the other 8 patients exhibited L chains of both types. The single "bitypic" population so tested was relatively polydisperse electrophoretically. As a comparison, anti-Rh(o) isoantibodies from 5 of 6 donors without known hematologic disease showed bitypic reactions, and 2 of these isoantibody populations were relatively polydisperse electrophoretically. One Rh isoantibody is described which contained only 1 demonstrable L chain type. The structural similarities to "paraproteins" observed in a significant proportion of these erythrocyte autoantibodies raise the possibility of their origin from a restricted population of antibody forming cells, and may have implications concerning the pathogenesis of erythrocyte autosensitization.