Dr. Robert Peuß (Stowers Institute for Medical Research)
in: 'Frontiers in Ecology and Evolution': "Investigating immunopathology in an eco-immunological framework: How parasite diversity shapes the evolutionary trajectory of the immune system"
by Dr. Robert Peuß (Stowers Institute for Medical Research)
Host-parasite interactions are one of the major driving forces in evolution. The loss of parasite diversity in modern societies in the last 200 years, however, strongly correlates with an increase of autoimmune diseases caused by immune-regulatory defects in humans. This indicates that the interactions between host and parasite not only created a co-evolutionary dynamic, but also represent a necessity for a vertebrate host to develop a functional immune phenotype. So far, this “Old Friends” hypothesis is largely based on descriptive data from humans since there are no suitable model organisms available that adapted to an environment with low parasite diversity. Here, we introduce Astyanax mexicanus as a new model organism for host-parasite interactions to specifically shed light on the question of how the loss of parasite diversity influences the evolution of the vertebrate immune system. We found that not only key innate immunological functions like phagocytosis are strongly decreased in cave populations of A. mexicanus, but inflammatory responses towards bacterial antigens are highly increased. Furthermore, to explore differences in the cellular organization of the immune system, we designed a new tool for morphological analysis of immune cells using semi-supervised, high-throughput imaging and advanced clustering algorithms. With the help of this tool, we found striking differences in the immune cell composition between cave dwelling and surface A. mexicanus. Future investigation in this direction will not only provide important insights into the immune system of the emerging model organism A. mexicanus in general, but will also help to elucidate the evolutionary trajectory of vertebrate hosts in an environment with low parasite diversity.