IBA Publikation

Walter de Gruyter

Abstract:
The age-related decline in immune system functions is responsible for the increased prevalence of infectious diseases and the low efficacy of vaccination in elderly persons. In particular, the number of peripheral naive T cells declines throughout life and they exhibit severe functional defects in older age. However, we have recently identified a non-regulatory CD8+CD45RO+CD25+ T cell subset that occurs in a subgroup of healthy elderly persons, who still exhibit an intact humoral immune response following influenza vaccination. We here demonstrate that CD8+CD45RO+CD25+ T cells share phenotypic and functional characteristics with naive CD8+CD45RA+CD28+ T cells from young persons, despite their expression of CD45RO. CD8+CD45RO+CD25+ T cells also have long telomeres and upon antigenic challenge, they efficiently expand in vitro and differentiate into functional effector cells. The expanded population also maintains a diverse T cell receptor repertoire. In conclusion, CD8+CD45RO+CD25+ T cells from elderly persons compensate for the loss of functional naïve T cells and may therefore be used as a marker of immunological competence in old age. Copyright Walter de Gruyter Verlag, 2008. Biological Chemistry, ISSN 1431-6730, eISSN 1437-4315