Glycoconjugates and their use as potential vaccines against infection by Shigella flexneri

A vaccine composition comprising a physiologically acceptable vehicle and a conjugate comprising an oligo or polysaccharide (Ib) selected from the group consisting of:

• (X)x-{BCDA}n-(Y)y-W
• (X)x-{CDAB}n-(Y)y-W
• (X)x-{DABC}n-(Y)y-W
• (X)x-{ABCD}n-(Y)y-W
• Wherein:
• A is a beta-d-Galacturonic (1,3) acid residue,
• B is a N-protected-beta-d-Galactosamine (1,2) residue, wherein said N-protecting group is an acetyl group, or a precursor thereof such as a N-trichloroacetyl group,
• C is an alpha-I-Rhamnose (1,2) residue, wherein at most one of 3c or 4c is OAc,
• D is an alpha-I-Rhamnose (1,4) residue,
• x and y are independently selected among 0 and 1,
• n is an integer comprised between 2 and 10,
• X and Y are independently selected among A, B, C, D, AB, BC, CD, DA, ABC, BCD, CDA, DAB,
• provided that the ratio of 3C-OAc/4C-OAc is greater than 1,
• wherein each OH and/or CO2H group of said residues are optionally protected by a protecting group,
• W is ORi, SRii or Hal, wherein said O, S and Hal are the C1 heteroatom of the reducing end residue of the oligo- or polysaccharide chain, S being optionally oxidized,
• Ri is H, a hydroxyl protecting group, an anomeric hydroxyl activating group, or a LZ group, L and Z being as defined above for formula (Ia),
• Rii is C1-C12 alkyl, C6-C10 aryl, an imidate leading preferably to S-thiazolinyl (STaz) or S-benzoxazolyl (SBox).

An oligosaccharide which is selected from the group consisting of:

• Benzyl (4-O-benzyl-3-O-para-methoxybenzyl-α-I-rhamnopyranosyl)-(1→2)-(3,4-di-O-benzyl-α-I-rhamnopyranosyl)-(1→4)-(allyl 2,3-di-O-benzyl-β-d-galactopyranosid)uronate,
• Allyl (4-O-benzyl-3-O-para-methoxybenzyl-α-I-rhamnopyranosyl)-(1→2)-(3,4-di-O-benzyl-α-I-rhamnopyranosyl)-(1→4)-(benzyl 2,3-di-O-benzyl-β-d-galactopyranosyluronate)-(1→3)-4,6-di-O-benzyl-2-deoxy-2-trichloroacetamido-β-d-galactopyranoside,
• 3,4,6-Tri-O-benzyl-2-deoxy-2-trichloroacetamido-α/β-d-galactopyranosyl N-phenyltrifluoroacetimidate,
• Allyl (2,3-di-O-benzyl-β-d-galactopyranosyl)-(1→3)-4,6-di-O-benzyl-2-deoxy-2-trichloroacetamido-β-d-galactopyranoside,
• Allyl (benzyl 2,3-di-O-benzyl-β-d-galactopyranosyluronate)-(1→3)-4,6-di-O-benzyl-2-deoxy-2-trichloroacetamido-β-d-galactopyranoside,
• Allyl (benzyl 2,3-di-O-benzyl-4-O-levulinoyl-β-d-galactopyranosyluronate)-(1→3)-4,6-di-O-benzyl-2-deoxy-2-trichloroacetamido-β-d-galactopyranoside,
• (Benzyl 2,3-di-O-benzyl-4-O-levulinoyl-β-d-galactopyranosyluronate)-(1→3)-4,6-di-O-benzyl-2-deoxy-2-trichloroacetamido-α/β-d-galactopyranose,
• Benzyl 2,3-di-O-benzyl-4-O-levulinoyl-β-d-galactopyranosyluronate-(1→3)-4,6-di-O-benzyl-2-deoxy-2-trichloroacetamido-α/β-d-galactopyranosyl N-phenyltrifluoroacetimidate,
• Benzyl 2,3-di-O-benzyl-4-O-levulinoyl-β-d-galactopyranosyluronate-(1→3)-4,6-di-O-benzyl-2-deoxy-2-trichloroacetamido-α/β-d-galactopyranosyl trichloroacetimidate,
• (3,4-Di-O-benzyl-2-O-levulinoyl-α-I-rhamnopyranosyl)-(1→4)-(benzyl 2,3-di-O-benzyl-β-d-galactopyranosyluronate)-(1→3)-4,6-di-O-benzyl-2-deoxy-2-trichloroacetamido-α/β-d-galactopyranosyl N-phenyltrifluoroacetimidate,
• (4-O-Benzyl-3-O-para-methoxybenzyl-2-O-levulinoyl-α-I-rhamnopyranosyl)-(1→2)-(3,4-di-O-benzyl-α-I-rhamnopyranosyl)-(1→4)-(benzyl 2,3-di-O-benzyl-β-d-galactopyranosyluronate)-(1→3)-4,6-di-O-benzyl-2-deoxy-2-trichloroacetamido-αβ-d-galactopyranosyl N-phenyltrifluoroacetimidate.