Immunology in wild nonmodel rodents: an ecological context for studies of health and disease

Abstract

Transcriptomic methods are set to revolutionize the study of the immune system in naturally occurring nonmodel organisms. With this in mind, the present article focuses on ways in which the use of 'nonmodel' rodents (not the familiar laboratory species) can advance studies into the classical, but ever relevant, epidemiologic triad of immune defence, infectious disease and environment. For example, naturally occurring rodents are an interesting system in which to study the environmental stimuli that drive the development and homeostasis of the immune system and, by extension, to identify where these stimuli are altered in anthropogenic environments leading to the formation of immunopathological phenotypes. Measurement of immune expression may help define individual heterogeneity in infectious disease susceptibility and transmission and facilitate our understanding of infection dynamics and risk in the natural environment; furthermore, it may provide a means of surveillance that can filter individuals carrying previously unknown acute infections of potential ecological or zoonotic importance. Finally, the study of immunology in wild animals may reveal interactions within the immune system and between immunity and other organismal traits that are not observable under restricted laboratory conditions. Potentiating much of this is the possibility of combining gene expression profiles with analytical tools derived from ecology and systems biology to reverse engineer interaction networks between immune responses, other organismal traits and the environment (including symbiont exposures), revealing regulatory architecture. Such holistic studies promise to link ecology, epidemiology and immunology in natural systems in a unified approach that can illuminate important problems relevant to human health and animal welfare and production.

Risk alleles for tuberculosis infection associate with reduced immune reactivity in a wild mammalian host

“…Multiscale studies of infectious diseases in wild populations can yield discoveries in applied and basic aspects of infectious disease biology, and build upon laboratory-based studies. For example, foundational ecoimmunology work in wild rodents has uncovered dramatic differences in immune function between laboratory mice and their wild congeners [5,6,10], demonstrating that simply giving disease a real-world environmental context can shift findings dramatically. Building upon this work, putative candidate genes for tolerance have been identified in wild rodents and tied to gene expression-based biomarkers, connecting animal-level disease to fine-scale gene expression patterns [11,12].…”

Changing expression of vertebrate immunity genes in an anthropogenic environment: a controlled experiment

“…Thus inbred mouse lines, unlike humans and domesticated animals, are genetically homogenous [ 10 ] and even outbred stocks may show restricted genetic variability [ 11 ]. Furthermore laboratory rodents are maintained under extremely benign and pathogen-free conditions, whereas humans and domesticated animals still encounter many infections and environmental insults, albeit that these are different to those occurring in nature [ 12 ]. Moreover, the singular genealogies of laboratory rodents make them difficult to compare directly with wild counterparts, even leaving the effects of inbreeding aside.…”

Profiling of the TCRβ repertoire in non-model species using high-throughput sequencing

“…Taken together, our work broadens knowledge of the immune system of the bank vole–a well-established species in ecological and evolutionary research, and an emerging, non-murine model in the field of eco-immunology and studies of zoonosis 66 , 67 . We showed that an informative analysis of an individual TCR repertoire is possible with partial information on the genomic composition of the TCR locus (e.g., we did not have full sequences of genomic segments prior to somatic recombination and had only provisional assignment to the actual loci for V and J segments).…”