Dynamical system in biology

by Prof. Leonid Bunimovich,

Thursday 20 Jun 2024, 14:30 → 15:30 Europe/Rome

Abstract - For many diseases with highly mutable viruses (Hepatitis C, HIV, Influenza, Dengue, etc) a person (host) carries a large collection of viruses which form a network thanks to the cross-immunoreactivity (CR). The last means that viruses may generate production of antibodies not only against themselves but also against some other viruses. In classical models of viral diseases this CR network was always considered to be homogeneous and studied by the mean field approach. However, these models were unable to explain various experimental observations associated with the establishment of chronic infections by highly mutable viruses. A new model (introduced with CDC colleagues) allowed to explain all such observations. This highly nonlinear model (which actually is somewhat simpler than previous ones by considering less variables) demonstrates cooperation between viruses, which allows them to fool the immune system and develop a chronic disease. It happens because some (altruistic) viruses sacrifice themselves in order to protect some other (persistent) viruses which become practically invisible to the immune system. It results in a local immunodeficiency because viruses become persistent thanks to their location and connections in cross-immunoreactivity networks. This finding (discovery) was published by us in PNAS. The analysis of this new nonlinear dynamical system was conducted then in papers published in J. of Theoretical Biology, Mathematical Biosciences. J. of Computational Biology, Bulletin of Math. Biology, etc. The last thing is that it allowed to find differences in networks of patients with acute and chronic forms of disease. THE TALK WILL BE CLEAR (no need to know any biology).