Abstract: Techniques for preparing stable conjugates of protein-D-GL which can then be isolated in pure form are disclosed, using hen egg ovalbumin (OVA) as a prototype protein, and conjugation and purification methods are described which involve (1) application of a coupling method employing m-maleimidobenzoyl-N-hydroxysuccinimide ester (MBS) as the coupling reagent, and (2) introduction of biotin moieties into D-GL molecules to allow application of avidinbiotin system for affinity chromatographic purification of conjugates. These methods are applicable to the preparation of D-GL conjugates of insulin and Ragweed Antigen E and are of general applicability.

Abstract: Immunosuppressive agents which are conjugates of an antigen linked to a D-glutamic acid:D-lysine copolymer are disclosed. Also disclosed are methods of preparing the conjugates and therapeutic methods for inducing immunological tolerance to antigens.

Abstract: The discovery of an isomeric species of carcinoembryonic antigen and methods of isolation, identification and utilization of the same as an aid in the diagnosis of adenocarcinomas of the gastrointenstinal tract are disclosed.

Abstract: The discovery of an isomeric species of carcinoembryonic antigen and methods of isolation, identification and utilization as a radiolabelled species of the same as an aid in the diagnosis of adenocarcinomas of the gastrointestinal tract are disclosed.