Recent Progress of Polysaccharide Conjugate Vaccines

Polysaccharide conjugate vaccines, a category of important vaccines formed by covalent linkage between bacterial capsular polysaccharides and carrier proteins, are used for preventing specific communicable diseases. The conjugates generated by coupling polysaccharide antigens with carrier proteins can convert T cell-independent antigens (polysaccharides) into T cell-dependent antigens, thereby inducing specific immune responses in infants and young children, promoting antibody affinity maturation, and ultimately exerting immune protective effects. Currently, such vaccines are widely applied in clinical practice with significant value; however, there are still many problems in the manufacturing process, including the need for large-scale cultivation of pathogenic bacteria, the use of highly toxic activating reagents, difficulty in uniform control of polysaccharide peptide chain length, unclear information on the binding sites and binding quantity between polysaccharides and proteins, as well as practical challenges such as low yield and high price of the final product. This article reviews the research progress of polysaccharide conjugate vaccines, aiming to provide reference for improving the production process of existing products and designing more rational vaccine candidates by systematically reviewing the research status of polysaccharide conjugate vaccines.