A world-first discovery has revealed special immune cells called ‘killer T cells’ in older adults, directed against influenza viruses, closely resemble those found in newborns and children, but struggle to recognize infected cells – a finding that unlocks the potential for the development of better vaccines and therapies tailored to different age groups.
Killer T cells (also known as CD8+ T cells) play a critical role in the immune system by eliminating virus-infected cells. While much has been studied about these immune cells in adults, little was known about how they evolve and function across the human lifespan – until now.
In a pioneering research published in Nature Immunology and led by the Peter Doherty Institute for Infection and Immunity (Doherty Institute) and UNSW Sydney, researchers employed cutting-edge technologies to examine killer T cells in different age groups – newborns, school-aged children, adults and older adults (60+ years) – to understand how age shapes our immunity to influenza viruses.
University of Melbourne’s Dr Carolien van de Sandt, a Senior Research Fellow at the Doherty Institute and first author of the paper, said the team uncovered unexpected similarities in T cell responses between newborns/children and older adults.
“Based on previous studies, we expected to find that killer T cells in older adults were less effective because they had become exhausted or ‘fallen asleep’,” said Dr van de Sandt.
“However, to our surprise, the very efficient killer T cells that we detected in children and adults seemed to actually disappear