Figure 2.

A diagrammatic representation linking (I) hosts ability to either resist pathogen growth, by immune activation, or (II) tolerate pathogen burden, by reducing the fitness costs of infection or immune activation without directly reducing the pathogen numbers to (III) the outcome of immune priming (i.e., post-infection survival benefits after priming relative to unprimed controls) or basal infection response (i.e., survival response to infection without prior priming relative to uninfected control). At the mechanistic level, a complex interplay between immune pathways & molecules, host metabolism, epigenetic reprogramming and host-associated microbiota might be collectively responsible for evolving priming vs basal immunity and infection responses. Figures on tolerance and resistance are adapted from Råberg et al., 2007.