Model immunogenic conjugated constructs based on dextran and detoxified Shigella sonnei lipopolysaccharide as a built-in adjuvant
AbstractIntroduction. One of the promising directions in the creation of new antibacterial glycoconjugate vaccines is the synthesis and study of protective preparations with a built-in adjuvant (BA), which can act as an agonist of toll-like receptors (TLRs), localized on the surface of many immunocompetent cells, in particular, macrophages and dendritic cells. The development of an approach to the synthesis of model conjugated constructs based on bacterial dextran and detoxified lipopolysaccharide (d-LPS) opens up the possibility of obtaining effective preventive and therapeutic preparations containing polysaccharide fragments of bacterial nature.
Aim – to synthesize conjugates of bacterial dextran and d-LPS Shigella sonnei, where connection is carried out due to the terminal D-glucose residue of dextran and the amino groups of the O-specific polysaccharide d-LPS, and also to evaluate the level of specific antibody response to the synthesized conjugates in experiment on mice.
Material and methods. Fractions of S. sonnei, phase 1 d-LPS with high and low molecular weight were obtained according to previously described methods. Each stage of the synthesis of activated dextran derivatives and conjugates was carried out under reductive amination conditions in the presence of sodium cyanoborohydride: 1) introduction of adipine dihydrazide (ADH) to the terminal dextran D-glucose residue; 2) introduction of an active aldehyde group through the reaction of ADH-derived dextran with glyoxal (GO), and 3) conjugation of activated ADH-GO-dextran with d-LPS S. sonnei, phase 1. The immunogenicity of the resulting preparations was estimated by the production of specific IgG antibodies in mice in response to immunization with the resulting conjugates
Results. As a result of the reaction of activated ADH-GO-dextran with high and low molecular weight fractions of d-LPS from S. sonnei, phase 1, the corresponding conjugates were obtained in high yield. Their structure was confirmed using NMR and mass spectrometry. The effectiveness of using GO to create «bridge» structures in the synthesis of conjugated constructs has been demonstrated. A study of the level of serum specific IgG to dextran fragment of the resulting conjugates in the blood of double administrated mice showed formation of reliable immune response.
Conclusion. The possibility of creating immunogenic conjugates with a new type of built-in BA has been demonstrated. Model constructs have been obtained in which bacterial dextran is used as a «weak» immunogen, and d-LPS from S. sonnei, phase 1, is used as BA. It is assumed that within the framework of this scheme, immunogenic conjugates can be obtained, which may include O-specific polysaccharides isolated from LPS, bacterial CPS, their oligosaccharide fragments, as well as synthetic oligosaccharides.
Keywords: dextran; detoxified lipopolysaccharide; Shigella sonnei; buit-in adjuvant
For citation: Lvov V.L., Filatov A.V., Savin A.P., Shatilov A.A., Shatilova A.V., Mislavsky O.V., Verner I.K., Smirnov V.V., Khaitov M.R. Model immunogenic conjugated constructs based on dextran and detoxified Shigella sonnei lipopolysaccharide as a built-in adjuvant. Immunologiya. 2025; 46 (1): 16–29. DOI: https://doi.org/10.33029/1816-2134-2025-46-1-16-29 (in Russian)
Funding. The study was carried out within the framework of a state assignment: «Synthesis and study of the biological characteristics of conjugated constructs based on the O-antigenic polysaccharide of Shigella flexneri and detoxified high-molecular lipopolysaccharide of Shigella sonnei as an adjuvant matrix for the development of a combined vaccine against Sonne and Flexner shigellosis», code: «Vaccine-24» with financial support from the Federal Medical and Biological Agency. Open publication of the research results is allowed.
Conflict of interests. Authors declare no conflict of interests.
Authors’ contribution. Concept and design of the study – Lvov V.L.; isolation, purification and detoxification of lipopolysaccharides, production of conjugates – Lvov V.L., Filatov A.V., Savin A.P.; recording mass spectra – Shatilov A.A., Shatilova A.V.; immunization of laboratory animals Mislavsky O.V.; immunogenicity study of resulting substances – Verner I.K.; writing the article – Lvov V.L., Filatov A.V., Verner I.K.; approval of the final version of the article – Smirnov V.V., Khaitov M.R. All authors contributed to the editing of the article and approved the final version.
References
1. Lvov V.L., Verner I.K., Gushchin V.A., Vasina D.V., Antonova N.P., Grigorev I.V. Method for obtaining Streptococcus pneumoniae capsular polysaccharides of vaccine quality, free from C-polysaccharide impurities. Immunologiya. 2024; 45 (6): 766–76. DOI: https://doi.org/10.33029/1816-2134-2024-45-6-766-776 (in Russian)
2. Lee C.J., Lee L.H., Lu C.S., Wu A. Bacterial polysaccharides as vaccines--immunity and chemical characterization. Review Adv Exp Med Biol. 2001; 491: 453–71. DOI: https://doi.org/10.1007/978-1-4615-1267-7_30
3. Avdeev S.N., Alyeva M.Kh., Baranov A.A., Bikmieva A.V., Briko N.I., Bulgakova V.A., Vishneva E.A., Gorelov A.V., Demko I.V., Dobrynina E.A., Drapkina O.M., Zhdanov K.V., Zhestkov A.V., Zaitsev A.A., Ignatova G.L., Kozlov R.S., Korshunov V.A., Kostinov K.M.P., Kulichenko T.V., Lobzin Yu.V., Mazankova L.N., Namazova-Baranova L.S., Polibin R.V., Rtishchev A.Yu., Selimzyanova L.R., Sidorenko S.V., Tatochenko V.K., Tkacheva O.N., Fedoseenko M.V., Feldblum I.V., Kharit S.M., Chulanov V.P., Shubin I.V. Vaccine prevention of pneumococcal infection in children and adults. Methodical recommendations. Preventive medicine. 2023; 26 (9): 3–23. DOI: https://doi.org/10.17116/profmed2023260923 (in Russian)
4. Immunoprophylaxis of meningococcal infection in children. Guidelines for the prevention of disease/syndromes. Ministry of Health of the Russian Federation. 2017. (in Russian)
5. Qingjiang L., Zhongwu G. Recent advances in Toll like receptor-targeting glycoconjugate vaccines. Molecules. 2018; 23 (7): 1583–607. DOI: https://doi.org/10.3390/molecules23071583
6. Coffman R.L., Sher A., Seder R.A. Vaccine adjuvants: putting innate immunity to work. Immunity. 2010; 33: 492–503. DOI: https://doi.org/10.1016/j.immuni.2010.10.002
7. Awate S., Babiuk L.A., Mutwiri G. Mechanisms of action of adjuvants. Front Immunol. 2013; 4: 114–24. DOI: https://doi.org/10.3389/fimmu.2013.00114
8. Avci F.Y., Kasper D.L. How bacterial carbohydrates influence the adaptive immune system. Annu Rev Immunol. 2010; 28: 107–30. DOI: https://doi.org/10.1146/annurev-immunol-030409-101159
9. Jarczak D., Nierhaus A. Cytokine storm-definition, causes, and implications affiliations. Int J Mol Sci. 2022; 23 (19): 11740–70. DOI: https://doi.org/10.3390/ijms231911740
10. Ohto U., Fukase K., Miyake K., Shimizu T. Structural basis of species-specific endotoxin sensing by innate immune receptor TLR4/MD-2. Proc Natl Acad Sci USA. 2012; 109 (19): 7421–6. DOI: https://doi.org/10.1073/pnas.1201193109
11. Dyatlov I.A., Svetoch E.A., Mironenko A.A., Eruslanov B.V., Firstova V.V., Fursova N.K., Kovalchuk A.L., Lvov V.L., Aparin P.G. Molecular lipopolysaccharide di-vaccine protects from Shiga-toxin producing epidemic strains of Escherichia coli O157:H7 AND O104:H4. Vaccines. 2022; 10 (11): 1854–71. DOI: https://doi.org/10.3390/vaccines10111854
12. Ledov V.A., Golovina M.E., Alkhazova B.I., Lvov V.L., Kovalchuk A.L., Aparin P.G. A pentavalent Shigella Flexneri LPS-based vaccine candidate is safe and immunogenic in animal models. Vaccines (Basel). 2023; 11 (2): 345–60. DOI: https://doi.org/10.3390/vaccines11020345
13. Robbins J.B., Kubler-Kielb J., Vinogradov E., Mocca C., Pozsgay V., Shiloach J., Schneerson R. Synthesis, characterization, and immunogenicity in mice of Shigella sonnei O-specific ligosaccharide-core-protein conjugates. Proc Natl Acad Sci USA. 2009; 106 (19): 7974–8. DOI: https://doi.org/10.1073/pnas.0900891106
14. Molinaro A., Holst O., Di Lorenzo F., Callaghan M., Nurisso A., D’Errico G., Zamyatina A., Peri F., Berisio R., Jerala R., Jimenez-Barbero J., Silipo A., Martin-Santamaria S. Chemistry of lipid A: at the heart of innate immunity. Chemistry. 2015; 21 (2): 500–19. DOI: https://doi.org/10.1002/chem.201403923
15. Casella C.R., Mitchell T.C. Putting endotoxin to work for us: Monophosphoryl lipid A as a safe and effective vaccine adjuvant. Cell Mol Life Sci. 2008; 65 (20): 3231–40. DOI: https://doi.org/10.1007/s00018-008-8228-6
16. Raetz C.R.H., Reynolds C.M., Trent M.S., Bishop R.E. Lipid A modification systems in gram-negative bacteria. Annu Rev Biochem. 2007; 76: 295–329. DOI: https://doi.org/10.1146/annurev.biochem.76.010307.145803
17. Raetz C.R.H., Whitfield C. Lipopolysaccharide endotoxins. Annu Rev Biochem. 2002; 71: 635–700. DOI: https://doi.org/10.1146/annurev.biochem.71.110601.135414
18. Sarkar A.K., Das M.K. Production of antibodies to dextran using liposome as adjuvant. 1991; 20 (3): 243–52. DOI: https://doi.org/10.3109/08820139109026227