1 HIV Dynamics and Immuno-Senescence Wayne M. Getz Department of Environmental Science, Policy & Management, University of California, Berkeley CA 94720-3112. Tel: 1-510-642-8745. Fax: 1-510-666-2352. email: getz@nature.berkeley.edu Submitted to AIDS for publication in the Research Letters section Length (words): Abstract 74; Text 991; Fig Caption: 236 ABSTRACT Three differential equations modeling HIV virion, and infected and uninfected immune-cell densities during acute and chronic phases of infection underlie in-vivo HIV viral-dynamics models. Adding a fourth equation that simulates immuno- senesence through the drawdown of a stem cell reservoir permits the phase of full- blown AIDS to be incorporated in the model. This greatly enhances the utility of the model in designing interventions and explains why time-to-full-blown AIDS decreases with age at infection. * Article