Evaluation of novel adjuvants to improve bacterial vaccines during immunosenescence

Summary 

Progressive functional and structural alterations in the immune system caused by age in humans result in heightened vulnerability to bacterial infections and diminished protective efficacy of conventional vaccines. Adjuvants are substances added to some vaccines to stimulate and enhance the immune response to induce a more effective immunisation. With adjuvants, the immune responses can be substantially more robust and long-lasting, especially for vaccines containing highly purified antigens with insufficient intrinsic immunostimulatory capabilities. Turbo, a novel vaccine adjuvant formulated with bacterial vaccines, shows promise in inducing long-lasting and highly protective immune responses across all ages in pre-clinical models, reducing the need for vaccine boosters for bacterial vaccines. We will assess the effect of ageing on the innate immune response of human cells to Turbo using adjuvant exploratory in vitro studies of antigen-presenting cells derived from older adults. We will further assess the immunogenicity of a Shigella dysenteriae type 1 vaccine candidate adjuvanted with Turbo using an aged animal model. This will enable us to propose the mechanism of action of adjuvants that can overcome immunosenescence and simultaneously support the development of a vaccine candidate against Shigella dysenteriae type 1, an antimicrobial-resistant bacteria particularly affecting older adults.