Immunogenic Properties of α(1 → 6) Dextran, Its Protein Conjugates, and Conjugates of Its Breakdown Products in Mice

Abstract

Mice were immunized with .alpha.(1-6) dextran, either as such or coupled to protein carriers; their anti-dextran [antibody] response was measured by a solid-phase radioimmunoassay and the Farr assay. Like earlier investigations, the protein-conjugated dextran was more antigenic than plain dextran. A standard dose (30 .mu.g of dextran/injection) coupled to strongly antigenic protein (chicken serum albumin (CSA)) was 3 times more antigenic than dextran coupled to weakly antigenic bovine serum ablumin (BSA). Dextrans of low MW (1000-10,000 daltons) coupled to CSA induced at least 10 times stronger secondary responses than did a similarly coupled macromolecular dextran (5-40 million daltons). Variation of the CHO[carbohydrate]/protein ratio from 0.3 to 1 had little effect on the antigenicity of the dextran. Increase of the ratio from 1 appeared to decrease immunogenicity when BSA was the carrier but not when CSA was the carrier.