Effects of Ageing on Adaptive Immune Responses
Sian M. Henson
Persistent viral infections, reduced vaccination responses, increased autoimmunity, and a rise in inflammatory syndromes all typify immune ageing. As lifespan continues to extend, the demographic shift towards an older population will highlight the need to understand the mechanisms that drive age-related immune dysfunction, and to identify strategies to improve immune responsiveness in older people. These changes can be in part attributed to the accumulation of highly differentiated senescent T cells, characterised by their decreased proliferative capacity and the activation of senescence signaling pathways, together with alterations in the functional competence of regulatory cells, allowing inflammation to go unchecked. Moreover these defects that account for the decline in immune responsiveness also contribute to an increased prevalence in autoimmunity, through the reshaping of the peripheral T cell repertoire. This chapter discusses how the age-associated remodelling of the immune system leads to a lack of stability and subsequent decline in immune function.
T cell • Lymphocyte differentiation • Senescence • Ageing • CD28 • TCR • mTOR • Regulatory • Immunosuppressive • Inflammation