Oral Presentation 20th Lancefield International Symposium on Streptococci and Streptococcal Diseases 2017

Examining the effects of host-glycan expression patterns in Group A streptococcal disease (#91)

David MP De Oliveira 1 , Arun E Dass 2 3 , Lauren Hartley-Tassell 3 , Christopher J Day 3 , David J McMillan 4 , Victor Nizet 5 , Mark J Walker 6 , Nicolle H Packer 2 3 , Michael P Jennings 3 , Martina L Sanderson-Smith 1
  1. School of Biological Sciences and Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
  2. Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW, Australia
  3. Institute for Glycomics, Griffith University, Gold Coast, QLD, Australia
  4. Inflammation and Healing Research Cluster, School of Health and Sports Sciences, University of the Sunshine Coast, Sippy Downs, QLD, Australia
  5. Centre for Immunity, Infection and Inflammation, University of California, San Diego, CA, USA
  6. Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia

Colonisation of the oropharynx is the initial step in Group A streptococcal (GAS) pharyngeal infection, facilitating continual asymptomatic carriage and disease spread. Over 600 million cases of pharyngitis are reported each year with approximately 15% of school children suffering from GAS pharyngitis in developed countries. The incidence rate in developing countries is 5 times higher. We have previously reported that the highly virulent M1T1 GAS clone mediates attachment to oral epithelial cells via M1 protein interaction with blood group antigen carbohydrate structures. Here, we have identified that like M1-type GAS, throat tropic GAS serotypes M3 and M12 have distinct and varying binding affinities for ABO blood group antigen and Lewis antigen structures. Investigation of GAS binding to oral epithelial cells suggests susceptibility to oral tract infection by GAS may correlate with phenotypic differences in host blood group antigen expression. Fucose, galactose, N-acetylgalactosamine and sialic acid are fundamental structures of blood group and Lewis antigen synthesis. Exoglycosidase treatment of primary human oral epithelial cells identified that terminal β1-3,4 galactose and α2-3 sialic acid structures mediate colonisation of M1, M3 and M12 GAS. Furthermore, the presence of α1-2 fucose and α1-3 N-acetylgalactosamine, determinants of H- and A-blood group antigens respectively, significantly alters the level of GAS attachment to oral epithelial cell surfaces. These data highlight how differences in host glycosylation patterns may affect GAS colonisation. Overall, this work may facilitate future studies to design multi-valent mimetics for blocking glycan mediated GAS colonisation of the upper respiratory tract.