Identifying cross-protective immune responses between Streptococcus pneumoniae and Group B Streptococcus [Early Career Investigator Project]

Principal investigators: Gaurav Kwatra, University of the Witwatersrand; Simon Jochems, Liverpool School of Tropical Medicine / Malawi Liverpool Wellcome Trust Research Programme

The mucosal pathogens Streptococcus pneumoniae (Spn) and Group B Streptococcus (GBS) are together responsible for a large proportion of early childhood mortality worldwide. Currently, there is no licensed vaccine against GBS and the Spn conjugate vaccine are poorly matched against circulating strains in LMIC, are expensive and suffer from serotype replacement. Novel vaccine strategies that combat streptococcal infections are urgently needed and being able to target both pathogens through one vaccine would provide a cost-effective method of delivering protective immunity and reducing streptococcal disease. There is some evidence suggesting that induction of cross-protective immunity between these two pathogens might exist. Analysis from some of the first genotyped GBS strains demonstrated a significant overlap with the Spn genome as 176 genes were shared between the two species. In a recent study of Gambian infants, nasopharyngeal carriage of GBS negatively correlated with Spn carriage. Moreover, the GBS type 3 capsule-induced antibodies cross-react with Spn type 14 capsular polysaccharides. In this project, we aim to explore the potential of inducing cross-protective immunity to these 2 streptococcal pathogens.