Establishing the relative importance of antibodies to emm type-specific and conserved antigens in protection from colonisation and disease due to Streptococcus pyogenes in The Gambia

Summary 

Streptococcus pyogenes, also known as Strep A, is a bacterium that causes severe infections in humans. Approximately half a million people die from Strep A infections each year, predominantly in low resource settings.  The creation of a vaccine to protect against Strep A is therefore a top priority. However, progress is slow in part due to our limited knowledge of exactly how the immune system responds to Strep A and provides protection against infection. One of the challenges in creating a vaccine is knowing which parts of the bacteria to target. There are two main strategies in the development of a vaccine; 1) targeting parts of the bacteria that would be present in all strains and 2) targeting the parts of the bacteria (the M protein) which make each strain unique. 

Our aim is to understand how antibodies develop with increasing age and following exposure to unique strains of bacteria, and to explore the extents that antibodies generated to unique strains protect from infection.

 In our research, we will use samples collected over one year from 442 people in The Gambia where rates of infection were high. We will measure antibodies by expanding a technique we have already developed at the MRC Unit The Gambia. We will explore if antibodies to particular strains are associated with reduced risk of infection from that strain, from similar strains and from unrelated strains. This understanding will help guide the strategy to eventually role out the most effective vaccine against Strep A in high burden settings like The Gambia.