Before revision:  To achieve a long-term benefit for the host, we show that memory generation should be actively regulated and dependent on immune receptors ' affinity, with a preference for cross-reactive receptors with a moderate affinity against pathogens as opposed to high affinity receptors -- a recipe that is consistent with recent experimental findings 1,2 . Moreover, we show that the specificity of memory should depend on URLanism's lifespan, and URLanisms with fewer pathogenic encounters throughout their lifetime should store more cross-reactive memory.
After revision:  To achieve a long-term benefit for the host, we show that memory generation should be actively regulated 1,2 . Moreover, we show that the specificity of memory should depend on URLanism's lifespan, and URLanisms with fewer pathogenic encounters throughout their lifetime should store more cross-reactive memory.