The main focus of the Physico-chemical Analysis Group is to evaluate the quality of saccharide-protein conjugate components and bacterial protein antigens. The following indicators of a vaccine’s quality are evaluated:
Our laboratory characterises and evaluates the stability of polysaccharide standards established for the quantitative potency determination in Typhoid, Haemophilus influenzae type b and Meningococcal vaccines. Participation in WHO Collaborative Studies led by the NIBSC for assignment of unitage and to determine how the standard will perform in real situations is often of mutual benefit to the WHO-sponsored project and the individual participants.
We carry out formal batch release of licenced glyco-conjugate or protein based products for the U.K., European and rest of the world on Haemophilus influenze type b and serogroups A, C, W and Y meningococcal, pneumococcal and typhoid conjugate vaccines to the requirements of WHO and UK Independent Control Testing guidelines. Contract or collaborative evaluation of new products (covering GBS, meningococcal and typhoid vaccines), often for global markets, are also performed, for the purpose of quality comparisons through different approaches to explore the strengths and limitations of particular methods used for characterization or control.
Our laboratory evaluates new vaccines, protein antigens or carrier proteins by optical spectroscopic or chromatographic methods to look at conformation, size and integrity, and to study how these correlate with markers of immunogenicity. Circular dichroism and fluorescence spectroscopy are used to evaluate the 2° and 3° structure of proteins, while SEC-MALLS/Viscosity is utilized to more accurately gauge the quaternary structure, hydrodynamic radius, aggregation status and viscosity of vaccine materials in stability studies.In addition to analyzing the protein components, we also evaluate saccharide and lipid components with HPAEC-PAD and RP-HPLC. Micro-flow imaging particle analysis (> 1 µm) adds a further dimension to formulation studies. Our long-term goal is to achieve a better understanding for the molecular basic of immunoprotection.
Hitri K., Kuttel MM, De Benedetto G, Lockyer K, Gao F, Hansal P, Rudd TR, Beamish E, Rijpkema S, Ravenscroft N, Bolgiano B. (2019) O-acetylation of typhoid capsular polysaccharide confers rigidity and immunodominance by masking additional epitopes. Vaccine 37, 3866-3875.https://doi.org/10.1016/j.vaccine.2019.05.050
Beresford NJ, Martino A, Feavers IM, Corbel MJ, Bai X, Borrow R, Bolgiano B. Quality, immunogenicity and stability of meningococcal serogroups ACWY-CRM197, DT and TT glycoconjugate vaccines. Vaccine 2017 Jun 10;35(28):3598-3606. http://dx.doi.org/10.1016/j.vaccine.2017.03.066
Lockyer K, Gao F, Derrick JP, Bolgiano B. (2015) Structural correlates of carrier protein recognition in tetanus toxoid conjugated bacterial protein vaccines. Vaccine 33, 1345-1352. http://dx.doi.org/10.1016/j.vaccine.2015.01.046
Jumel K, Ho MM, Bolgiano B. (2002) Evaluation of Meningococcal C oligosaccharide conjugate vaccines by size exclusion chromatography/multi-angle laser light scattering. Biotechnology Applied Biochemistry 36, 219-226. https://doi.org/10.1042/BA20020066
https://doi.org/10.1016/j.jmb.2006.09.050Ho MM, Bolgiano B, Corbel MJ. (2000) Assessment of the stability and immunogenicity of meningococcal oligosaccharide C-CRM197 conjugate vaccines. Vaccine, 19, 716-725. https://doi.org/10.1016/S0264-410X(00)00261-9
Barbara Bolgiano, Group LeaderFang (Frank) Gao, Deputy Group LeaderNicola Beresford, Deputy Group LeaderKarena Burkin, ScientistKay Lockyer, Analytical ScientistGianluigi De Benedetto, Analytical Scientist