How Can We Improve the Vaccination Response in Older People? Part II: Targeting Immunosenescence of Adaptive Immunity Cells

Abstract

The number of people that are 65 years old or older has been increasing due to the improvement in medicine and public health. However, this trend is not accompanied by an increase in quality of life, and this population is vulnerable to most illnesses, especially to infectious diseases. Vaccination is the best strategy to prevent this fact, but older people present a less efficient response, as their immune system is weaker due mainly to a phenomenon known as immunosenescence. The adaptive immune system is constituted by two types of lymphocytes, T and B cells, and the function and fitness of these cell populations are affected during ageing. Here, we review the impact of ageing on T and B cells and discuss the approaches that have been described or proposed to modulate and reverse the decline of the ageing adaptive immune system.

Keywords: B cells; T cells; adaptive immunity; aging; immunosenescence; vaccines.

Figure 1

T cell immunosenescence and response to vaccines. The figure summarizes the major characteristics of immunological aging. The degree of response to vaccination over time is schematically represented on top. Below, the anatomical and cellular characteristics associated with aging are represented.

Figure 2

Schematic representation of altered molecules in senescent T cells. During T cell senescence, multiple molecules are altered, among them molecules related to TCR signalling (grey), cell signalling (green), epigenetics and transcription factors (purple), membrane receptors (brown) and cytokines (pink).