Let's Go Wild

(March 28th, 2011) Eco-Immunology is slowly becoming a research field on its own but it took some time to get there. Amy Pedersen (with some editorial help from Simon Babayan) from the University of Edinburgh lets you in on the difficulties of establishing a whole new research field.

Lab Times: How did you first encounter “Eco-Immunology”?

My training is in the ecology and evolution of infectious disease, and for the majority of my research career I have focused on trying to understand the interaction between hosts and their parasites/pathogens in natural populations. I have, until recently, focused on how parasites can negatively affect their host, and how these interactions translate to changes at the population level. However, the more I studied parasites in natural populations, the more I realised that most individuals are infected by lots of very diverse parasite taxa and that the potential for within host interactions between parasites, either directly or indirectly through shared resources or the immune response, was very likely and important for the health and fitness of the host. The field of “eco-immunology” has been interested in understanding the role of immune responses in an ecological and evolutionary context, specifically to understand variation in immune function across individuals, with a focus on determining the fitness consequences of such variation. I looked to this newly developed field to begin to address these complex interactions between hosts and parasites. Since arriving at the University of Edinburgh I have been collaborating with Simon Babayan and a few other laboratory immunologists, to further develop and address these immunological questions.

Lab Times: What, in your opinion, is the most important finding so far?

I think that the field of ecoimmunology is quite young, and so the techniques and applications are still being developed. A general and important finding of ecoimmunology is that there is great variation in the immune responses generated by individuals in natural populations. While we have known that there is variation in immune responses in laboratory model systems and in humans, in natural populations we may be able to conduct experiments and test how this variation in immune responses may influence the spread of pathogens and affect host fitness. I think the most significant piece of work to be published thus far was by Andrea Graham and colleagues in Science in 2010, titled ‘Fitness correlates of heritable variation in antibody responsiveness in a wild mammal’. The authors investigated a wild/unmanaged population of Soay sheep and found that, counter-intuitively, elevated markers of auto-immunity, which other studies have found to be associated with lower infection burdens, were correlated with higher fitness. This is one of the first studies to link robust laboratory immunological tools to a measure of host fitness in a natural population.

Lab Times: Is there a difference between “wild immunology” (as referred to on your website) and “eco-immunology”?

I believe that the goals of ‘wild immunology’ and ‘eco-immunology’ are generally the same, to link the immune response of an individual to host fitness in a natural environment. Traditionally, eco-immunology studies in wild populations have focused on measuring a single or very few general measures of immunocompetence, however, it is unlikely that a single immune measure will predict the outcome of infection or the impact on host health. Our recent paper called ‘Wild Immunology’ suggests that aiming for a single immunocompetence measure is not a realistic benchmark, and it is more likely that there will be a suite of interacting components of the immune response that will determine, whether a host survives an infection. Wild immunology thus aims to bring the vast toolbox and expertise of laboratory immunologists into the field to tackle these difficult, yet important questions about how variation in immune responses contribute to host health and fitness, and in the process to help immunologists appreciate the importance of the mechanisms they study in natural settings.

Lab Times: Could you briefly explain why it is so important to “take immunology to the wild”?

Life in the wild is tough. Individuals face ecological pressures that will affect their health and fitness. Many of these pressures will also affect immune function and the costs associated with mounting an immune response. Yet the vast majority of our knowledge of the immune system is from the lab where animals have a constant supply of food and water, limited genetic variability and a more or less completely controlled environment. If we are to tackle the pressing issues of human, domestic animal and wildlife health that we currently face, one important step may be to test our vast knowledge of laboratory immunology in the wild, where conditions are far from controlled but may represent the true challenges for humans and wild animals.

Lab Times: How difficult is it to establish a new field? What is needed?

Eco-immunology has been developing steadily over the last 20 years, and has been receiving more and more attention. We are in the early days but there is a lot of excitement and enthusiasm for developing and contributing to this new area of research.

Lab Times: How about funding? Is anyone willing to invest in such a young discipline?

Several groups working on eco-immunology have received funding from traditional research council funding agencies but, importantly, we are perceiving a lot of interest from the scientific community (i.e. established immunologists and ecologists), which is very promising. Our wild immunology group in Edinburgh has been awarded pilot grants and funds to hold a one-day symposium on Wild Immunology. This symposium is supported by the Wellcome Trust funded Centre for Infection, Immunity and Evolution and will be held at the University of Edinburgh on June 30th (for more details: http://ciie.bio.ed.ac.uk/).

Lab Times: There are still a lot of problems concerning reagents for non-model animals, picking the best suited method and properly interpreting obtained results. In your latest article you suggested measuring “as many factors as possible” but this sounds very time-consuming and pricey.

That is absolutely true. To do wild immunology, it will take a significant investment in creating appropriate tools and techniques. But once these immunological, genomic and/or post-genomic tools have been developed, they should be applicable to many ecoimmunological questions and possibly several host-parasite systems. These costs may be great, at least initially, but are probably unlikely to be more expensive than current laboratory immunological studies that include extensive animal husbandry.

Lab Times: Several groups are working on ecoimmunological questions in Edinburgh, why is the field so strong there?

The University of Edinburgh has a strong tradition of research in both evolutionary biology and infection and immunology, as well as interdisciplinary projects between these two groups. Recently, several research groups, both ecologists/evolutionary biologists and laboratory immunologists have become interested in immunological questions in natural systems, and so we have come together to form this “Wild Immunology” initiative.

Lab Times: What do you expect from eco-immunology in the future?

We hope that bringing the tools and techniques of immunology into wild systems will (1) contribute to our understanding of the dynamics of natural populations and (2) inform the development of medical intervention strategies for humans, whom are about as genetically and environmentally diverse as the wild systems we study. The great potential of wild immunology is that it is possible to conduct experimental studies with large cohorts and over multiple generations in a wild system. This approach is not possible in humans and quite difficult in domesticated animals. Lastly, by linking immune responses to parasites and host fitness in these experimental studies, we increase the power of our analyses and, importantly, are able to address the fitness consequences of immune variation.

Interview: Kathleen Gransalke

Photos: Amy Pedersen, University of Edinburgh

Last Changes: 08.03.2012