José Borghans,
Associate Professor of Immunology at  University Medical Centre Utrecht

This lecture will focus on different studies on the quantification of T-cell dynamics in healthy people and laboratory animals. It shows how the quantification of T-cell dynamics has revealed a fundamental difference in the maintenance of naive T cells between mice and humans. It also addresses the dynamics of T cells in patients after stem-cell transplantation, and shows that it is questionable whether the human immune system is capable of inducing a successful homeostatic response to low lymphocyte numbers. Finally, it focusses on recent insights into memory T-cell dynamics. We show that cellular longevity is not a key characteristic of memory T cells. Importantly, insights into immunological memory in humans are almost exclusively based on studies of cells from the blood. It has recently been suggested that the bone memory provides a niche for long-lived memory T cells that hardly recirculate through the blood and therefore go unnoticed in most immunological studies.