Capsular polysaccharide (PS) is a T cell-independent antigen that directly activates B cells without the help of CD4+ T cells. However, this PS is unable to induce durable specific memory B cells in adults. The researchers have found that zwitterionic polysaccharide (ZPS) conjugates are more immunogenic than PS conjugates. CD BioGlyco is an expert in ZPS-based adjuvant development according to every special need.
Carbohydrates are thought to be T cell-independent antigens that induce weak antibody responses by priming the innate immune system. It has been reported that ZPS belongs to bacterial capsular heteropolysaccharides with a high density of positive and negative charges. ZPS is obtained by chemically incorporating positive charges into anionic polysaccharides. Unlike other carbohydrate antigens, ZPS is a T-cell-dependent antigen that activates antigen-presenting cells (APCs) in humans and mice through toll-like receptor 2 (TLR2). Meanwhile, ZPS also has further immunostimulatory properties.
Studies have shown that ZPS is a T cell-dependent antigen that is recognized and activated by Th cells. ZPS is presented in B cells by MHCII, and binds to T cells after nitric oxide oxidation, acidification, and in vivoprocessing. This activates T cells to produce cytokines and binds to B cells, resulting in the conversion of IgM to IgG, producing memory B cells and high-affinity IgG antibodies. In addition, the researchers proposed that the interaction and co-stimulation between the ZPS-MHCII complex and the T cell receptor, leads to the production of the cytokine interferon-γ (IFNγ) by Th cells.
Fig.1 The proposed action mechanism of ZPS adjuvants. (Pifferi, 2021)
The unique chemical structure and activity of ZPS have inspired researchers' enthusiasm for exploration. Through structural analysis of ZPS, it is proposed that the key to ZPS immune activity is that the α-helix and ZPS motif appear as alternating positive charges and negative charges on monosaccharide residues pointing to opposite sides of the helix. CD BioGlyco develops new ZPS conjugates by chemically modifying native bacterial PS. For example, ZPS adjuvants have been obtained by chemical modification to introduce positive charges into native anionic group B Streptococcus PL. Meanwhile, we provide chemical synthesis services for ZPS repeating units, such as PS A1, Sp1, CP5, and CP8.
CD BioGlyco has been focused on carbohydrate adjuvants for many years and has accumulated knowledge and experience. Our experienced scientists and cutting-edge Glyco™ Vaccine Development Platform will help you accelerate your adjuvant project development. If you are interested in our ZPS-based adjuvant development service, please contact us directly.
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