Conjugation Methods in Synthetic Glycoconjugate Vaccines

In the past two to three decades, synthetic glycoconjugate vaccines have shown great potential in the prevention of severe infections and protection of high-risk populations. Conjugation of synthetic oligosaccharide haptens to carrier proteins is the key step for the vaccine preparation. In this review, the conjugation methods currently used in the synthesis of glycoconjugate vaccines from synthetic/homogeneous oligosaccharide haptens are summarized with the focus on the reaction conditions (pH and sugar/protein ratio) and performance. This information can help researchers choose the appropriate conjugation methods. Further research directions toward site-specific conjugations and fully homogeneous glycoconjugate vaccines are also discussed.