RT Journal Article SR Electronic T1 A dynamical motif comprising the interactions between antigens and CD8 T cells may underlie the outcomes of viral infections JF bioRxiv FD Cold Spring Harbor Laboratory SP 540054 DO 10.1101/540054 A1 Baral, Subhasish A1 Antia, Rustom A1 Dixit, Narendra M. YR 2019 UL http://biorxiv.org/content/early/2019/02/05/540054.abstract AB Some viral infections culminate in very different outcomes in different individuals. They can be rapidly cleared in some, cause persistent infection in others, and mortality from immunopathology in yet others. The conventional view is that the different outcomes arise as a consequence of the complex interactions between a large number of different factors (virus, different immune cells and cytokines). Here, we identify a simple dynamical motif comprising the essential interactions between antigens and CD8 T cells and posit it as predominantly determining the outcomes. Antigen can activate CD8 T cells, which in turn can kill infected cells. Sustained antigen stimulation, however, can cause CD8 T cell exhaustion, compromising effector function. Using mathematical modelling, we show that the motif comprising these interactions recapitulates all the outcomes observed. The motif presents a new conceptual framework to understand the variable outcomes of infection. It also explains a number of confounding experimental observations, including the variation in outcomes with the viral inoculum size, the evolutionary advantage of exhaustion in preventing lethal pathology, the ability of NK cells to act as rheostats tuning outcomes, and the role of the innate immune response in the spontaneous clearance of hepatitis C. Interventions that modulate the interactions in the motif may present novel routes to clear persistent infections or limit immunopathology.