Preparation and Immunologic Comparison of Antibodies to Closely Related Antigens Produced in Individual Rabbits¹

A procedure for the isolation of two antibodies specific for very similar antigens, glucosyl-phenylazo bovine serum albumin and galactosyl-phenylazo bovine serum albumin, from doubly-immunized individual rabbits is described. Immunoelectrophoretic and ultracentrifugal analyses of these purified antibodies failed to reveal differences between them, indicating only one 7 S component for each; while total amino acid analyses and total sugar analyses also failed to reveal differences in composition. Factors which may be responsible for their difference in specificity are discussed.