Biochemical characterization of canine blood group antigens: immunoprecipitation of DEA 1.2, 4 and 7 and identification of a dog erythrocyte membrane antigen homologous to human Rhesus

Despite the clinical significance of the canine blood group antigens, relatively little is known of the biochemistry of these molecules. In this study the canine blood group antigens DEA (dog erythrocyte antigen) 1.2, 4 and 7 were immunoprecipitated from red blood cells (RBC) bearing the corresponding blood group, and molecular weights of 85 kD (DEA 1.2), 32–40 kD (DEA 4) and 53–66 kD (DEA 7) assigned. DEA 1.2 and DEA 4 each appeared as a single band, whereas DEA 7 comprised three distinct bands (53, 58 and 66 kD). Polyclonal antisera specific for two peptides derived from the sequence of the human Rhesus blood group (Rh30A-C and Rh50A-C) were used in western blotting against carine and human erythrocyte membranes. The Rh30A-C antiserum identified a band of molecular weight 32 kD in both human and canine RBC, and the antiserum specific for Rh50A-C identified a band of 38–60 kD in human membranes and of 40–53 kD in canine RBC. This finding is consistent with conservation of areas of the Rhesus protein sequence between human and canine erythrocytes.