Synthesis and immunochemical evaluation of a novel Neisseria meningitidis serogroup A tetrasaccharide and its conjugate

A tetrameric repeating unit of capsular polysaccharide (CPS) of Neisseria meningitidis A (MenA) containing phosphodiester α-(1→6) linkages between N -acetyl-3- O -acetyl- d -mannosamine moieties was synthesized with excellent yield using stereoselective glycosyl phosphorylation strategy. The synthesized tetrasaccharide was conjugated with tetanus toxoid protein (TT) to furnish a glycoconjugate derivative in satisfactory yield. The immunochemical properties of the tetrasaccharide and semi-synthetic glycoconjugate derivative were evaluated for the development of a potential MenA vaccine candidate.