Optimal immune specificity at the intersection of host life history and parasite epidemiology

Abstract

Epidemiology and life history are commonly hypothesized to influence host immune strategy, and the pairwise relationships between immune strategy and each factor have been extensively investigated. But the interaction of these two is rarely considered, despite evidence that this interaction might produce emergent effects on optimal immune strategy. Here we investigate the confluence of epidemiology and life history as it affects immune strategy through a demographically-framed model of sensitivity and specificity in parasite recognition and response. We find that variation in several different life history traits associated with both reproduction and longevity alters optimal immune strategies – but the direction and magnitude of these effects depends on how epidemiological risks vary across life. Drawing on published life history data, we also find that our predictions apply across chordate taxa. Our results shed light on the complex interactions shaping immune strategy and may prove valuable in interpreting empirical results in ecoimmunology.

Dynamics of immune memory and learning in bacterial communities

“…Phenomenological models of pathogen co-evolution with the immune system have accelerated our understanding of how the fitness landscape generated by the immune system constrains pathogen evolution [12, 13, 7, 14, 15], how the adaptive immune system responds to rapid pathogen evolution [16, 17, 14, 15], and what drives pathogen extinction [7, 13] or the extinction of particular clonal cell lineages [17, 10]. These models have also explored trade-offs such as between immune receptor specificity and cross-reactivity [4, 18], between the specifity of host-pathogen discrimination and sensitivity to pathogens [8, 19, 20], between the speed of an immune response and the efficiency of that response [14], or between metabolic resource use and immune coverage [15]. All of these models have shown rich dynamics and qualitatively different states of diversity and evolution arising from simple rules.…”