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Professor Jeremy Brown

Institute: University College London

Global identification of protein antigen antibody responses after exposure to live attenuated Streptococcus pneumoniae

Streptococcus pneumoniae (also called the pneumococcus) is the commonest cause of pneumonia worldwide, causing up to 3 million deaths each year. Most of these deaths are in low and middle income countries (LMICs).

Current approved vaccines for adults are not very effective at preventing pneumococcal pneumonia, so there is an urgent need for improved ones to reduce the number of deaths caused by the infection.

Streptococcus pneumoniae
Streptococcus pneumoniae
Image: wikimedia commons

Many people are pneumococcal ‘carriers’ – they have a low-level infection of the bacteria at the back of the throat without having any symptoms. This harmless throat colonisation generates an immune response that protects carriers from more serious forms of the infection (including pneumonia).     

This suggests that giving non-carriers a dose of bacteria in a nasal spray to mimic harmless throat colonisation could act as a vaccine and protect them against getting pneumonia. The pneumococcal bacteria we are testing as potential vaccines are genetically engineered (attenuated) to make them safe.

We are using a human infection study programme established in Liverpool to test how effective the potential vaccine is, and to find out if the attenuated bacteria in the vaccine is as good as natural pneumococcal bacterial at protecting people from re-infection.   

In this project, we will use a new method that provides much more detail about the immune response, so we can more fully compare natural and attenuated bacterial infections. Additionally, we will analyse samples from people in Malawi with natural pneumococcal infections to compare their immune responses to trial volunteers in the UK.

These experiments will help us understand more about immune reactions to pneumococcal infections in high and low risk people in different locations, and compare the genetically engineered bacteria in a potential vaccine with natural infection. It will be a step towards setting up clinical trials in Malawi to test a potential new vaccine, with the goal of reducing the number of deaths caused by pneumococcal pneumonia.

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