A polysaccharide derivative composed of a backbone of linear octasaccharide derivative repeating units consisting of beta-QuiN4Fm-(1->4)-alpha-GalNAcAN-(1->4)-alpha-GalNAcAN-(1->3)-beta-QuiNAc-(1->2)-beta-QuiN4Fm-(1->4)-alpha-GalNAcAN-(1->4)-alpha-GalNAcAN-(1->3)-beta-QuiNAc connected by beta-(1->2) linkages.