Study of Specificity of Anti-Human Globulin (Coombs\u27) Serum for Normal Serum Fractions by the Agar Plate Precipitin Technique of Ouchterlony

The discovery of blocking anti-Rh antibodies was soon followed by the description of the anti-human globulin test by Coombs, Mourant and Race (1645, 1946). Rabbit serum produced against human gamma globulin proved to be a powerful tool for the detection of incomplete antibodies coating human red blood cells. The appearance of antibodies with different specificities in antiglobulin sera is to be expected since the antigen used for stimulation is not a simple one. Coombs sera are standardized with human erythrocytes sensitized by Anti-D (Anti-Rho) antibodies which are presumably gamma globulins (National Institutes of Health Minimum Requirements for the production of Anti-Human Serum for the Anti-Globulin Test, 1949). It has now been well established that not all blood group antibodies are gamma globulins. It is therefore desirable that Coombs reagents detect the non-gamma globulin varieties of antibodies as well as those which are gamma globulins. There is great variation in the ability of available lots of Coombs serum to agglutinate erythrocytes sensitized with non-gamma globulin antibodies largely because methods have not been established to standardize these reagents for the presence of the necessary antibodies. The application of the principle of the gamma globulin neutralization test of Dacie (1951) has made it possible to establish the existence of anti-non-gamma globulin as well as anti-gamma globulin antibodies in Coombs sera (Dacie 1951, 1953: Cutbush 1955; Crawford and Mollison 1951; Renton 1952). The diagnostic usefulness of these reagents in immunohematology makes it important to establish the specificities of the antibodies present. The purpose of this study is to estimate the number and to identify the specificity of the precipitation antibodies which are present in rabbit serum which has been produced by immunization with whole human serum