System biology models and conceptualizations applied to eco-immunology

Abstract

This article outlines how ecological concepts, based on population dynamics and mathematical models, can be helpful for investigating various aspects of immunology, and in particular immune responses against infectious diseases. The review starts by describing how basic ecological concepts have been applied to investigating the in vivo dynamics between immune responses in viral infections in vivo and discusses the usefulness and limitations of such approaches. These concepts include predator-prey dynamics, competition between different clones of the same immune response, and competition between different branches of the adaptive immune system. The article continues to discuss how immune responses can be important modulators of pathogen competition in vivo, and this is explored with a particular example, i.e. the competition dynamics among different viral strains in the context of multiple infection of cells. Finally, these in vivo considerations are extended to examine how immune responses to infectious diseases can influence pathogen-host dynamics on an epidemiological levels. This is done with two examples: the effect of immunity on the apparent competition between two host species, and the effect of immunological memory on the strain composition of a pathogen population circulating in a host population. Overall, this article summarizes different aspects in which ecological concepts can be useful to understand concepts in immunology, discussing several different examples, spanning a variety of scenarios.