Abstract
The mammalian immune system protects individuals from infection and disease. It is a complex system of interacting cells and molecules and extensive work, principally with laboratory mice, has investigated its function. Wild and laboratory animals lead very different lives, and this is reflected in there being substantial immunological differences between them. Here we use network analyses to study a unique data set of 120 immune measures of wild and laboratory mice, where immune measures define nodes and correlations of immune measures across individual mice define edges between immune measures. To date, there has only been very limited network analyses of the immune system, which is surprising because such analyses may be important to better understand its organisation and functionality. We found that the immunological networks of wild and laboratory mice were similar in some aspects of their mesoscale structure, particularly concerning cytokine response communities. However, we also identified notable differences in node membership of network communities between the wild and laboratory networks, pointing to how the same immune system acts and interacts differently in wild and in laboratory mice. These results show the utility of network analysis in understanding immune responses and also the importance of studying wild animals in additional to laboratory animals.
Author summary The mammalian immune system is a complex system that protects individuals from infection and disease. Most of our understanding of the immune system comes from studies of laboratory animals, particularly mice. However, wild and laboratory animals lead very different lives, potentially leading to substantial immunological differences between them and so possibly limiting the utility of laboratory animals as informative model systems. As a complex interacting set of cells and molecules, the immune system is a biological network. Therefore, we used network analyses to study the immune system, specifically a unique data set of immune measures of wild and laboratory mice, where 120 different immune measures define nodes of the network. We found that the networks of wild and laboratory mice were similar in some aspects of their grouping structure, particularly concerning communities of nodes of cytokine responses. However, we also identified notable differences in node membership of communities between the wild and laboratory networks, pointing to how the same immune system behaves differently in wild and in laboratory mice. These results show the utility of network analysis in understanding immune responses and also the importance of studying wild animals in addition to laboratory animals.
