The generation of novel GBS conjugate vaccines using GBS common membrane proteins and GBS capsular polysaccharides

Summary

Streptococcus agalactiae or group B Streptococcus (GBS) bacterial infection is a major health concern and a leading cause of sepsis and meningitis in infants, particularly in Africa.

A promising prevention for GBS infection in new-borns is maternal immunization with a GBS vaccine. However, there is currently no vaccine for GBS available. Biovac is developing a traditional conjugate GBS vaccine using polysaccharides expressed on the surface of the GBS bacterium as antigens linked to tetanus toxoid as a carrier protein. 

As part of WHO’s target product profile for a GBS vaccine, a one-dose vaccination regimen has been recommended. It remains to be ascertained whether a single dose of a traditional maternal GBS conjugate vaccine will elicit a sufficiently protective immune response in newborns. To enhance the response to a vaccine, we are proposing a novel vaccine design using GBS surface proteins conjugated to GBS polysaccharides. GBS proteins common to all serotypes have been identified as inducers of immune responses in infected individuals, making them potential candidates for novel GBS vaccines. 

In this proof of concept project, we will conjugate a single GBS common protein to a single GBS polysaccharide with the aim to not only providing superior protection compared to traditional conjugate vaccines but to potentially provide protection against those serotypes not included in the vaccine. If successful, this will allow for the development of an affordable and cost-effective monovalent vaccine that protects against all GBS serotypes.


Seanette Wilson

Dr Seanette Wilson
Group Leader & Program Manager
The Biovac Institute (South Africa)

Collaborators:
Dr Gaurav Kwatra, University of the Witwatersrand (South Africa)

Dr Fatme Mawas, National Institute for Biological Standards and Control (UK)