Systematic simulation of cross-reactivity predicts ambiguity in Tk memory: it may save lives of the infected, but limits specificities vital for further responses.

The present study uses the agent-based model IMMSIM to simulate immune responses to a viral infection, with a focus on the impact of preformed memory (homologous and heterologous) on the quality and the efficacy of the response. The in machina results confirm the observed thwarting of new, naïve responses exerted by cross-reacting memory, but they also reveal that the competitive inhibition is made possible by the different time frame used by the primary and the secondary response, a well-known fact, epitomized by the interval of about 75 time steps between their peaks. This novel finding justifies the depression of naïve responses and the long-term consequences it could bring about and the role of memory as a player in a survival of the fittest game.