Synthesis and Preliminary Immunological Evaluation of a Pseudotetrasaccharide Related to a Repeating Unit of the Streptococcus pneumoniae Serotype 6A Capsular Polysaccharide

• Published in: Frontiers in molecular biosciences 2021-12, Vol.8, p.754753-754753
• Main Authors: Sukhova, Elena V, Yashunsky, Dmitry V, Kurbatova, Ekaterina A, Akhmatova, Elina A, Tsvetkov, Yury E, Nifantiev, Nikolay E
• Format: Article
• Language: English
• Subjects: capsular polysaccharide; conjugate vaccines; Molecular Biosciences; phosphodiester; repeating unit; Streptococcus pneumoniae serotype 6A; synthesis
• ISSN: 2296-889X; 2296-889X
• DOI: 10.3389/fmolb.2021.754753

2-Aminoethyl glycoside of the pseudotetrasaccharide α-d-Glc -(1→3)-α-l-Rha -(1→3)-d-Rib-ol-(5- 2)-α-d-Gal corresponding to a repeating unit of the type 6A capsular polysaccharide has been synthesized. A suitably protected pseudotrisaccharide α-d-Glc -(1→3)-α-l-Rha -(1→3)-d-Rib-ol with a free 5-OH group in the ribitol moiety and a 2-OH derivative of 2-trifluoroacetamidoethyl α-d-galactopyranoside have been efficiently prepared and then connected a phosphate bridge using the hydrogen phosphonate procedure. Preliminary immunological evaluation of this pseudotetrasaccharide and the previously synthesized pseudotetrasaccharide corresponding to a repeating unit of the capsular polysaccharide of serotype 6B has shown that they contain epitopes specifically recognized by anti-serogroup 6 antibodies and are able to model well the corresponding capsular polysaccharides. Conjugates of the synthetic pseudotetrasaccharides with bovine serum albumin were shown to be immunogenic in mice.