Enzymatic degradation and immunogenic properties of derivatized dextrans

Dextran T40 was modified with carboxylic, benzylamide and benzylamine-sulphonated groups (samples 1-10). The polymers were incubated with dextranase and the decrease of molecular weight was determined by high performance size exclusion chromatography. It was shown that the higher the substitution of dextrans, the lower their degradability. Modification of dextran with benzylamine and benzylamine-sulphonated groups appeared to hinder the formation of the enzyme-substrate complex more than the same quantity of carboxylic groups. The immunogenicity of one of the modified dextrans, containing 54% of carboxylic groups and 19.5% of benzylamine-sulphonated groups, was determined after subcutaneous and intravenous administration into Balb/c mice. The antibody titre was very low even if administered in complete Freund's adjuvant and did not depend on the injected dose. On the average, the titres of antibodies were lower by five orders of magnitude compared to bovine gamma globulin.