Fig. 1

Immunological changes associated with aging and adaptive immunosenescence. Specific changes in the T and B cell compartments are known to occur with aging and the onset of immunosenescence. Naïve lymphocyte production, lymphocyte repertoire diversity, and the proliferative and functional capacity of effector lymphocytes all decline with age; similarly, increases in differentiated memory cell populations, lymph node fibrosis, and altered cytokine production all occur. These phenomena have been collectively associated with diminished vaccine responses and an increased susceptibility to viral infectious diseases in older adults. The mechanisms by which immunosenescence operates are not fully understood, and systems biology approaches are currently focused on elucidating these mechanisms in order to inform the rational design of vaccines for older adults