Vaccination in the elderly: an immunological perspective

Abstract

Successful vaccination of the elderly against important infectious pathogens which cause high morbidity and mortality represents a growing public health priority. Building upon the theme of aging and immunosenescence, we review mechanisms of human immunosenescence and the immune response to currently-licensed vaccines. We discuss the difficulties in identifying the risk factors that, in addition to aging, cause immunosenescence and address the relative paucity of vaccine studies in the elderly. We conclude that vaccine responses are blunted in the elderly when compared to that of healthy young adults. However, it is also clear that our understanding of the mechanisms underlying immunosenescence is limited and much remains to be learned in order to improve the effectiveness of next generation vaccines.

IL-15 enhances the antitumor effect of human antigen-specific CD8+T cells by cellular senescence delay

“…24 Replicative senescence (telomere-dependent) usually occurs in T cells with shorter telomere length as a process of aging isolated in elderly people. [48][49][50][51] Premature senescence (telomere-independent), on the other hand, has many causes, such as DNA damage, oxygen stress, chromatin perturbation, and oncogene perturbation. [52][53][54][55] Extended in vitro culturing can cause senescence.…”

Senescence of the cellular immune response in Drosophila melanogaster

“…Decreasing abundance of naive B cells and an altered T cell repertoire result in a declining ability to form and retrieve immunological memories, leading to poor clinical responses to vaccination and infection late in life [4]. The major ageing-dependent pattern in innate immune defence is one of increasing dysregulation; one consequence may be heightened inflammatory responses, termed 'inflamm-aging' [5].…”

“…Two other haemocyte classes are present in [4] Drosophila: lamellocytes encapsulate foreign objects (such as parasitoid eggs) and crystal cells store phenoloxidase for release following immune activation [12]. However, lamellocytes and crystal cells are found only in larvae [13], and are therefore not relevant to immune system ageing in adults.…”

B Cells Compartment in Centenarian Offspring and Old People

“…These infections contribute significantly to morbidity in this age-group, and frequently lead to irreversible frailty and dependency. In addition, there is a decline in the protective effect of vaccination in the elderly [1][2][3][4][5][6][7]. Lifelong and chronic antigenic load seem to be the major driving force of immunosenescence, which impacts on human lifespan by reducing the number of virgin antigen-non experienced cells, and, simultaneously, filling the immunological space with expanded clones of memory and effector, antigen-experienced cells [7][8][9].…”