CD8 clonal expansions in mice: An age-associated alteration of CD8 memory t-cells

Abstract

Aging is associated with a variety of perturbations in the immune system. One frequent alteration is a significant skewing of the CD8 T-cell repertoire. This alteration manifests as a clonal expansion of CD8 memory T cells, which in some cases can occupy the majority of the CD8 T-cell pool. CD8 clonal expansions are associated with impaired immunity in the elderly. Although CD8 clonal expansions are commonly found in aging humans and mice, the etiology of this phenomenon is unknown. Here, we describe our current understanding of CD8 clonal expansions as it relates to the current state of knowledge about CD8 T-cell memory. In addition, we discuss the heterogeneity observed between different types of clonal expansions in mice, and how distinct factors may influence both the development and properties of clonal expansions in the aging individual.