The T cell branch of the immune system has been extensively studied in the elderly and it is known thatthe elderly have impaired immune function, mainly due to the chronic antigenic load that ultimatelycauses shrinkage of the T cell repertoire and filling of the immunologic space with memory T cells. In thepresent paper,we describe the IgD CD27 double-negative B cell population which (aswe have recentlydescribed) is higher in the elderly. Most of these cells were IgG+. Evaluation of the telomere length andexpression of the ABCB1 transporter and anti-apoptotic molecule, Bcl2, shows that they have themarkers of memory B cells. We also show that these cells do not act as antigen presenting cells, asindicated by the low levels of CD80 and DR, nor do they express significant levels of the CD40 moleculenecessary to interact with T lymphocytes through the ligand, CD154. Hence, we hypothesize that theseexpanded cells are late memory or exhausted cells that have down-modulated the expression of CD27and filled the immunologic space in the elderly. These cells might be the age-related manifestation oftime-enduring stimulation or dysregulation of the immune system.
|Numero di pagine||10|
|Rivista||Mechanisms of Ageing and Development|
|Stato di pubblicazione||Published - 2009|
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