Scientific Publications by FDA Staff

Vaccine 2007 Nov 14;25(46):7972-80

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.

Gudlavalleti SK, Lee CH, Norris SE, Paul-Satyaseela M, Vann WF, Frasch CE

Gudlavalleti SK (reprint author), US FDA, Ctr Biol Evaluat & Res, Lab Bacterial Polysaccharides, Room 109,Bldg 29,Lincoln Dr, Bethesda, MD 20892 USA US FDA, Ctr Biol Evaluat & Res, Lab Bacterial Polysaccharides, Bethesda, MD 20892 USA

Polysaccharide (PS) and tetanus toxoid (TT) protein conjugate vaccines were prepared using O-acetylated (OAc(+)), O-acetyl negative (OAc(-)) and chemically de-O-acetylated (de-OAc) meningococcal W135 PS. The PSs were activated by periodate oxidation and coupled to hydrazine derivatized TT. High performance anion exchange chromatography of acid hydrolysates of periodate activated W135 PSs, showed that galactose residues in OAc(+) PS were more sensitive to the periodate oxidation step than they were in the OAc(-) PS or de-OAc PS. Mouse antisera against OAc(-)-TT conjugate vaccines recognized both OAc(-) and OAc(+) PS by ELISAs and had high bactericidal titers against both OAc(+) and OAc(-) W135 strains. Purified high molecular weight (HMW) conjugates showed higher PS to protein ratios in OAc(-)-TT((HMW)) and de-OAc-TT((HMW)) indicating better conjugation efficiency than OAc(+)-TT((HMW)) conjugate. Antisera against the HMW fractions gave higher bactericidal titers than antisera against unfractionated conjugates. Inhibition ELISAs indicated that OAc(-) and OAc(+) HMW conjugates induced antibodies that bound both OAc(+) and OAc(-) PS. Thus, for W135, PS O-acetylation does not contribute a dominant immunogenic epitope. The OAc(-) PS may be a good starting material for preparing W135 PS-TT conjugate vaccines using periodate oxidation.