A mathematical model for the immunosenescence

We propose a model for the dynamics of the immune system by considering the subpopulations of virgin and memory T lymphocytes on a time scale correspo nding to the human life span. In the deterministic balance equation we intr oduce a fluctuating term in order to take into account the chronic antigeni c stress. Starting from the hypothesis that the depletion of virgin cells w ith cytotoxic properties (CD8+) is a mortality marker, the model provides s urvival curves quite similar to the demographic curves.