The newly launched iSpy Network (immunity to Streptococcus pyogenes) brings together 28 investigators from 11 countries worldwide. The iSpy Network comprises experts in immunology, infectious disease, epidemiology, vaccinology and experimental medicine, and include Bristol's Professor Adam Finn. It is led by Imperial College London alongside the University of California San Diego (UC San Diego), supported by funding from the Leducq Foundation.
Group A Streptococcus (or Strep A) commonly causes sore throat and skin infections in younger children and, more rarely, can trigger sepsis and toxic shock when the bacterium enters the bloodstream or tissue. Repeated exposure to Strep A infection can also cause autoimmune damage to the valves of the heart, known as rheumatic heart disease (RHD), which affects an estimated 50 million people worldwide, with most living in LMICs.
Adam Finn, Professor of Paediatrics at Bristol Medical School, added: "We are delighted to be involved in this ambitious project. Building on many years of research in Bristol on the mucosal immunity to bacteria induced by infections and vaccines in children, Drs Anu Goenka and Alice Halliday are developing novel techniques to understand immune protection against this dangerous pathogen, paving the way to design safe and effective vaccines to block its spread."
Strep A is highly transmissible and spreads from person to person mostly via the respiratory route from sore throats. Unlike children, adults are mostly immune to Strep A sore throats and skin infections. However, both groups are very susceptible to the invasive form of the infection.
Imperial's Professor Shiranee Sriskandan from the Department of Infectious Disease heads one of two iSpy sub-networks, called iSpy-LIFE. She said: "At present we don't fully understand how immunity to Strep A develops over time and if there are specific antigens (parts of the bacterium) that are more important for targeting by the immune system or future vaccines. It’s also unclear how overreaction by the immune system to Strep A – what we might call 'bad' immunity – leads to RHD and how that differs from the ‘good’, protective immunity we'd like to see."
The iSpy-LIFE sub-network will address this through studies in young children, school-age pupils and adults to investigate how ‘good’ immunity to Strep A develops in children after they naturally acquire infections over time. It is hoped this will give a better understanding of what makes people genuinely immune to Strep A, and how a vaccine might emulate and accelerate that immunity in children.
Meanwhile, the iSpy-EXPLORE sub-network will investigate the nature of protective immune cell and antibody responses in experimental animals that receive the most promising Strep A vaccine candidates currently in development. It will also examine how the human immune system reacts when healthy volunteers are experimentally challenged with Strep A infections. Taken together, the work will help scientists understand how we might measure ‘good’ and ‘bad’ immunity to Strep A, paving the way for a future vaccine that protects against strep throat, invasive infections and RHD.
Professor Adam Finn, Dr Anu Goenka and Dr Alice Halliday are all members of the Infection and Immunity Research Network supported by the Elizabeth Blackwell Institute.