Multiple Parameterisation of Human Immune Response in HIV: Many-Cell Models

Mathematical and computational models of the Human Immune Response have gained considerable attention over recent years and a number of approaches have been reported in the literature. One of the most successful relies on modelling, at cell level, the key components of the response using cellular automata/Monte Carlo strategies. However, a core issue remains the parameterisation required to demonstrate realistic evolution. We discuss a model of 8 cell-types, which can represent both T cell-mediated and humoral functions of the immune system, and focus on parameter sets, with values chosen to reflect realistic time-scales, comparable to natural biological processes. Analysis of the influence of the parameters introduced enables comparison of the properties of the 8-cell and basic models. In particular, a slightly reduced critical mutation value is found to lead to immune deficiency while, when a variable mutation growth factor is applied, immune breakdown occurs rapidly. The 8-cell model is susceptible to some reduction and aggregation, but system “fitness” dominates response.