Adjuvants are substances that stimulate the immune system, enhance immunogenicity, and have no specific antigenic effects themselves. Currently, many natural and synthetic carbohydrates have been used as adjuvants in clinical vaccine trials. Recently, two adjuvants have been approved for human vaccines. Different kinds of saponins and their derivatives have good adjuvant effects in antiviral and antitumor vaccines. CD BioGlyco provides customers with saponin-based adjuvant development services.
Saponins are a class of glycosides whose aglycones are triterpenoids or spirosterane compounds. They come from various plants of the Rhamnaceae, Araliaceae, Polygalaceae, and Leguminosae, and belong to plant-derived adjuvants. Saponins have a series of biological activities, such as antiviral, antitumor and antiallergic, etc. QS-21, an acylated saponin that stimulates humoral and cell-mediated immune responses, is identified as a potent Th1/Th2 cell adjuvant. QS-21 is also the most widely reported adjuvant and is used in clinical vaccines. However, QS-21 causes cell hemolysis and local toxic side effects. Therefore, researchers combined QS-21 and other components into adjuvant systems to improve the reactogenicity of vaccines.
When exogenous protein antigens and QS-21 are delivered to dendritic cells (DCs), the endosomal membrane is disrupted and the protein antigens are processed into smaller peptide fragments by the proteasome machinery. Transport molecules transport the degraded peptides into the endoplasmic reticulum, where they bind to newly synthesized MHC class I molecules and migrate through vesicles to the cell surface. Then, MHC-I-related peptide epitopes on the DC surface are presented to naive T cells via the T cell receptor (TCR). QS-21 activates cytokines, triggers a Th1-biased immune response, and produces IgG2a and IgG2b antibodies.
Fig.1 The action mechanism of QS-21 adjuvant. (Pifferi, 2021)
QS-21 is the choice adjuvant of clinical vaccines for numerous cancers and infectious diseases. It was recently approved as part of the GSK malaria and shingles vaccine adjuvant system AS01. The inherent scarcity, hydrolytic instability, heterogeneity, and dose toxicity limit the study of QS-21 as an independent clinical adjuvant. To address the inherent issues with QS-21 adjuvants, CD BioGlyco offers customers a variety of synthetic saponin variant adjuvant development services. We provide semi-synthetic saponin adjuvants by chemical derivatization of natural products or new saponin analogs. At the same time, according to the needs of customers, we provide customized saponin-based adjuvant development services.
CD BioGlyco is a leader in the development of carbohydrate-based adjuvants. We have accumulated rich experience in the field of saponin adjuvants development. We are pleased to share our knowledge and experience to advance the development of saponin adjuvants. If you are interested in our services, please contact us directly for more information.