Sources of individual variation in immune traits on a within individual, a between individual and a local/population scale
29 April 2016
UAntwerp - Campus Middelheim, A.143 - Middelheimlaan 1 - 2020 Antwerpen
Organization / co-organization:
Department of Biology
Wendt Müller & Marcel Eens
PhD defence Anke Vermeulen - Department of Biology
This thesis aimed to increase our understanding of what is also called wild immunology. That is studying the complexity and the adaptive significance of immunity and immune responses in wild animals. My focus was on the as yet relatively poorly explored innate branch of the immune system, which only recently became accessible amongst others because of methodological advancements. Innate immunity is a central and indispensable component of vertebrate immunity, since it serves as a first line of defence and at the same time it also initiates the subsequent actions of the adaptive immunity.
Yet despite the general agreement on the benefits of (innate) immunity, there is, as for most other physiological traits, a large amount of individual variation in baseline innate immune levels. The potential sources of this variation and even more so their functional consequences remained as yet unclear. So when I started working on this thesis, my aim was to increase the knowledge about the innate immune system, in order to be a small step closer to solving the complex puzzle concerning the costs and benefits of (variation in) innate immunity in the wild.
Because of the latter the aim was to work with free-living animals, since in general there is too little knowledge about the role of immunity in wildlife or on how immunity is affected by the natural conditions to which organisms are exposed. To achieve this, I chose to work with some field-friendly techniques that allow researchers to assess immunity with only one single blood sample. Further, each of these techniques required only a small volume of blood, which renders them extremely suitable for the research of this thesis, especially since I also aimed to look at several innate immune parameters at the same time.
When looking back on this research I conducted, the latter indeed seemed to be important for the overall understanding of immunity. This thesis tries to zoom in on the causes and consequences of variation at different levels, from among populations to within-individuals. I explored the impact of pollution, the potential importance and predicting capacities of natural variation in baseline innate immune traits and the consequences of ageing on the immune system in order to unravel the possible consequences of the existing variation in immune traits and to get a better understanding of the complex immune system.