The role of CEACAM receptors in streptococcal infections

1. To characterise the molecular mechanism of the R28IgI3 adhesin and CEACAM1 receptor interaction
2. To assess whether B and R28 induce CEACAM1 signalling
3. To define the function of CEACAM engagement with GBS and GAS in the context of epithelial cells
Carcinoembryonic antigen-related adhesion molecules (CEACAM) receptors are expressed on wide range of cells including epithelial cells and leukocytes. They modulate immune responses through forming homophilic and heterophilic interactions, and serve as docking sites for several human pathogens. We previously discovered that human streptococcal pathogens can express adhesins that bind human CEACAM receptors with high-affinity and high-specificity. This project will investigate how human streptococcal pathogens utilise CEACAM receptors to colonise mucosal surfaces and to cause invasive infections. We will combine various techniques including biochemical techniques and cellular infection assays. To complement this approach, we will utilise structural biology approaches to analyse host-pathogen interactions in molecular detail. As Streptococcal pathogens remain a significant and no vaccines currently exist, research into their virulence is of importance for development of novel therapeutic strategies.