Comparison of Neisseria meningitidis serogroup W135 polysaccharide–tetanus toxoid conjugate vaccines made by periodate activation of O-acetylated, non-O-acetylated and chemically de-O-acetylated polysaccharide

Bacterial polysaccharides as major surface antigens: interest in O-acetyl substitutions

“…Besides, better bactericidal titers against both O-acetyl positive and negative MenW strains were detected following immunization with conjugates encompassing an O-acetyl negative or a de-O-acetylated CPS component. 148 The study also shed light on the influence of the degree of Oacetylation of the sialic residue in MenW CPS on periodate oxidation and in turn on the 15 composition of the resulting conjugates. Acetylation at O-7 or O-9 can modify the availability of the more accessible exocyclic vicinal hydroxyl groups on the sialic acid, and therefore affect the involvement of galactose residues in periodate oxidationmediated coupling of MenW CPS to proteins.…”

“…148 In particular, although the O-acetyl positive CPS conjugate induced some O-acetyl specific antibodies, 10 these did not appear to contribute to the bactericidal effect. Besides, better bactericidal titers against both O-acetyl positive and negative MenW strains were detected following immunization with conjugates encompassing an O-acetyl negative or a de-O-acetylated CPS component.…”

“…Acetylation at O-7 or O-9 can modify the availability of the more accessible exocyclic vicinal hydroxyl groups on the sialic acid, and therefore affect the involvement of galactose residues in periodate oxidationmediated coupling of MenW CPS to proteins. 148 The authors concluded that the O-acetyl negative CPS may be a good starting material for preparing MenW conjugate vaccines 20 using periodate oxidation.…”

“…Despite the low abundance of O-acetylated strains and the demonstration that Oacetylation does not contribute to an important epitope in raising functional antibodies, 148 all licensed MenW CPS and conjugate vaccines contain an O-acetylated CPS component. Moreover, as for MenY, the pharmacopeial specifications for MenW CPS used in 25 vaccine production requires that more than 14.3% repeats be O-acetylated.…”

Development of a group A meningococcal conjugate vaccine,MenAfriVacTM

“…29 Use of activated PS and TT-H has also been applied to serogroup W135 conjugate vaccines. 30 Lot release testing of the different components of the meningococcal group A conjugate was done in reference to the 2006WHO recommendations for production of group A meningococcal conjugate vaccines. 32 The lot release tests shown in to improve the public health response to meningitis outbreaks in sub-Saharan Africa after the devastating outbreaks in 1996-1997.…”