Environment (\in-ˈvī-rə(n)-mənt) is a noun that refers to the sum of physical, chemical, and biological factors that act upon an organism or an ecological community, but can also refer to all social and cultural conditions that infl uence the life of an individual or community. Thus, the environment comprises factors as diverging as climate, microbes, lifestyle, stress, diet, sun exposure, chemical pollution, and much more. Ultimately, the environment determines how we can live.
The term “immune system” appeared fi rst in the early twentieth century and describes the many interacting and specialized body functions that protect from disease and infections. The immune system has evolved as the response of animals against bacteria, viruses, and fungi and it is most highly developed in vertebrate animals. It also serves to detect and eliminate cancer cells and contributes to epithelial integrity, thus protecting our barriers to the environment. Without our immune
system, we cannot survive. Manipulating the immune status by vaccination and drugs and dietary compounds and supporting immune competence by hygiene measurements have saved countless human lives.
Looking at the interaction and communication of the immune system with the environment, especially the chemical environment in the broadest sense, is an interdisciplinary exercise. In the last decades, research was limited often to niches such as immunotoxicology and immunopharmacology. This is currently changing. There is a growing awareness in mainstream immunology that environmental conditions and environmental factors far beyond infections can infl uence the immune system. The influence can strengthen or weaken the immune system, including vaccination success, or give relevant cues for the adaptive direction an effective immune response should take.
There is a great need to understand how this communication between the environment and the immune system works. In a modern world we must understand how chemicals and the environment affect health: people suffering from allergies or autoimmunity, cancer, or immune-related morbidity want answers. Better knowledge will open new avenues for preventive or therapeutic strategies, informed policy decisions, or changes towards a healthier personal lifestyle.