Assoc Prof Neil Ravenscroft
My research interest lies in applying chemistry and modern methods of physicochemical analysis to the field of biologicals, in particular vaccines. Bacterial pathogens expressing a glycocalyx are amongst the most important causes of death and morbidity in both the developing and developed worlds, particularly amongst the young and the elderly. The most important organisms wordwide include Streptococcus pneumoniae, Haemophilus influenzae type b, Staphlococccus aureus types 5 and 8, Groups A and B Streptococcus, diarrhoea-causing organisms such as Salmonella and Shigella, and gram negative coliforms (Klebsiella and E. Coli). Some other organisms, such as Neisseria meningitidis, are feared because of the rapid onset of disease and death. The problems associated with all these organisms are now exacerbated by the increasing incidence of antibiotic resistance. Glycoconjugate vaccines, constructed from part of the bacterial glycocalyx covalently attached to a protein carrier, are the most cost effective way of protecting the population against such diseases. Licensed conjugate vaccines against Haemophilus influenzae type b and meningococcal group C are available, and a number of vaccines against some of the diseases mentioned above are in development.
My research activities include:
(i) Establishing a Bioanalytical Centre for the development and application of modern physicochemical methods of analysis to the characterisation and quantification of biologicals in the fields of biochemistry, microbiology and medicine, with special emphasis on vaccines. The main techniques involve spectroscopy (NMR, mass and optical) and chromatography.
(ii) Structural studies of new carbohydrate antigens. These are from clinical isolates of enteric bacteria (e.g. Klebsiella) and from a collaboration with Dr P. Cescutti (Trieste. Italy) to study virulence factors of the opportunistic pathogen (Burkholderia cepacia) in cystic fibrosis (CF) patients.
(iii) Preparation and physicochemical characterisation of glycoconjugate vaccines against bacterial meningitis. Neisseria meningitidis group A is responsible for the massive epidemics of meningitis that periodically affect Africa, China and Latin America. However, no conjugate vaccine is available and therefore this is the main target for development. This project is a collaboration with Chiron Vaccines (Siena, Italy).
- Bacteriophage degradation of Klebsiella K30 capsular polysaccharide. An NMR investigation of the 3,4 pyruvylated galactose-containing repeating oligosaccharideN. Ravenscroft, L. A. S. Parolis & H. Parolis Carbohydr. Res., 254 (1994) 333 – 340.
- Structural elucidation of the Biological Repeating Unit of the O-Specific Polysaccharide from Citrobacter Serotype O41 by Gas-Liquid Chromatography and Two-Dimensional NMR Spectroscopy N. Ravenscroft, J. Dabrowski & E. Romanowska Eur. J. Biochem. 229 (1995) 299-307.
- Size determination of bacterial capsular oligosaccharides used to prepare conjugate vaccines. N. Ravenscroft, G. Averani, A. Bartoloni, S. Berti, M. Bigio, V. Carinci, P. Costantino, S. D’Ascenzi, A. Giannozzi, F. Norelli, C. Pennatini, D. Proietti, C. Ceccarini, & P. Cescutti Vaccine 1999, 17, 2802-2816.
- Quantitative determination of saccharide in Haemophilus influenzae type b glycoconjugate vaccines by high-performance anion-exchange chromatography with pulsed amperometric detection A. Bardotti, N. Ravenscroft, S. D’Ascenzi, G. Averani & P. Costantino Vaccine, 2000, 18, 1982-1993.
- Glycoconjugate vaccines N. Ravenscroft and C. Jones Curr. Opin. Drug Disc. Develop., 2000, 3, 222-231.
- Physicochemical characterisation of the oligosaccharide-component of vaccines, N. Ravenscroft, S. D’Ascenzi, D. Proietti, F. Norelli & P. Costantino Dev. Biol. Standards, 2000, 103, 35-47.
- The application of NMR spectroscopy to track the industrial preparation of polysaccharide and derived conjugate vaccines N. Ravenscroft PHARMEUROPA Special Issue, BIO-2000, 131-144.