Résumé : Living systems often attempt to calculate and predict the future state of the environment. Given the stochastic nature of many biological systems how is that possible ? Does host-pathogen co-evolution constrain the space viral trajectories? I will show that co-evolution between immune systems and viruses in a finite-dimensional antigenic space can be described by an antigenic wave pushed forward and canalized by host-pathogen interactions. This leads to a new emergent timescale, the persistence time of the wave's direction in antigenic space, which can be much longer than the coalescence time of the viral population.
Since predicting the future state of a viral environment requires weighing the trust in new observations against prior experiences, I will present a view of the host immune system as a dynamic Bayesian machinery that updates its memory repertoire by balancing evidence from new pathogen encounters against past experience of infection to predict and prepare for future threats