A highly efficient preparation of neoglycoconjugate vaccines using subcarriers that bear clustered carbohydrate antigens

A limited amount of spacer-equipped carbohydrate haptens was linked by reductive amination to a subcarrier, an oligopeptide containing 16 amino groups, to give a hapten-carrying subcarrier (HCS). It was then linked, via the remaining free amino groups, to chicken serum albumin (CSA) to give a cross-linked neoglycoconjugate bearing the haptens in the form of clusters. Alternatively, the same type of a glycoconjugate, but with higher conjugation efficiency, was obtained when HCS was treated successively with squaric acid diethyl ester and CSA.