The immune system exhibits profound age-related changes, collectively termed immunosenescence. The most visible of these is the decline in protective immunity, which results from a complex interaction of primary immune defects and compensatory homeostatic mechanisms. The sum of these changes is a dysregulation of many processes that normally ensure optimal immune function. Recent advances sugge...

Age-related alterations in the cellular composition of the B lineage are a major cause of the poor antibody response to vaccination and to infectious agents among the elderly population. The mechanisms leading to these changes are poorly understood. Recently, we have shown that these changes reflect, at least in part, homeostatic pressures imposed by long-lived B cells that accumulate with agin...

202 W E summarize here the fruitful discussion that occurred on a wide variety of topics during the session on stem cell aging. Somatic Stem Cell Aging Do stem cells age; and if they do, how can these changes be reliably identifi ed? Most attendees were of the view that a decline in the function of tissue-specifi c somatic stem cells is likely to play an important role in human aging. Results f...

The aged adaptive immune system is characterized by progressive dysfunction as well increased autoimmunity. This decline responsible for elevated susceptibility to infection and cancer, decreased vaccination efficacy. Recent evidence indicates that CD4+ T cell–intrinsic alteratins contribute chronic inflammation are sufficient accelerate an organism-wide aging phenotype, supporting the idea cel...

The stem cell theory of aging postulates that aging is the result of the failure of tissue specific stem cells to replenish tissues and to sustain tissue function. Stem cell functions decline with age, consistent with the degeneration and dysfunction of aging regenerative tissues. Stem cell dysfunction is associated with premature aging and evidence is emerging to suggest that stem cell manipul...

Aging is organized in a hierarchy, in which aging of cells results in aged tissues, ultimately limiting lifespan. For organ systems that also in the adult depend on stem cells for tissue homeostasis like the hematopoietic system that forms immune cells, it is believed that aging of the stem cells strongly contributes to aging-associated dysfunction. In this review, we summarize current aspects ...