Dendritic cells in human aging

Abstract

Dendritic cells (DCs) play a critical role in linking innate and adaptive immunity. A role of DCs in immunosenescence and chronic inflammation associated with aging has not been investigated in detail. In this article we will briefly review DCs biology and changes associated with human aging.

Aging of the Immune System as a Prognostic Factor for Human Longevity

“…Moreover, aging is associated with a reduction in the number of DC derived from myeloid precursors (18), which also have a more mature phenotype and an impaired ability to produce IL-12 with age (17,108). Other functions such as macropinocytosis, endocytosis, response to chemokines, and cytokine secretion are impaired, probably as a consequence of decreased activation of the phosphoinositide-3 kinase pathway (2). Together, these data suggest that some age-associated immune dysfunctions can originate from impaired DC functions.…”

Innate Immune Responses in the Geriatric Population

“…Several reports indicate that there are no significant differences in numbers of circulating myeloid and plasmacytoid DCs between older people and young subjects and that the www.intechopen.com expression of costimulatory molecules (CD86 and HLA DR) is similar (Agrawal et al, 2007a;Agrawal et al, 2007b;Pietschmann et al, 2000). In contrast, another study showed that numbers of myeloid DCs progressively declined with age while proportion of plasmacytoid DCs was unaffected.…”

“…Several studies used these in vitro cultured cells to assess the phenotype and functions of DCs in aged populations. Monocytederived DCs present no clear differences of costimulatory or activatory molecules (HLA-DR, CD80, CD86, CD40, CD83) except for CD25 and ICAM after lipopolysaccharide stimulation in healthy older individuals compared to younger (Agrawal et al, 2007b;Ciaramella et al, 2011;Agrawal et al, 2007a). Monocyte-derived DCs of older people are less efficient for micropinocytosis and phagocytosis of apoptotic cells and are impaired for migration (Agrawal et al, 2007b).…”

“…Myeloid DC : In vitro monocyte-derived DCs, cultured with GM-CSF+IL-4, are closely related to interstitial or myeloid DCs (Agrawal et al, 2007b). Several studies used these in vitro cultured cells to assess the phenotype and functions of DCs in aged populations.…”

“…Furthermore, DC maturation leads to the release of high levels of cytokines that are www.intechopen.com www.intechopen.com responsible for the regulation and polarization of both innate and acquired immune responses (Ciaramella et al, 2011;Agrawal et al, 2007a). DCs are heterogeneous and are subdivided into two major categories: those that are present in peripheral blood (myeloid and plasmacytoid DCs) and those that are present in tissue/organs (Langerhans cells, interstitial and interdigitating DCs) (Agrawal et al, 2007b). Myeloid DCs express CD11c+ and low level of CD123 and can be subdivided into CD16+ (40-80%), CD1b/c+ (20-50%) and BDCA3+ (2-3%) subpopulations (Figure 4).…”