Innate Immunity Under the Exposome of Space Flight
Host defense is key to survival of every living organism. The innate immune system, the evolutionarily oldest form of defense against invading pathogens, is present in all life and the result of long years of adaptation to the environment. A fast, less-specific reply to microbial threats using cellular and humoral components without the build-up of an immunological memory are its features. As we progress exploring the universe, manned space missions will become even more frequent and longer in duration. We are striving to explore the possibilities of permanently manned space stations like the International Space Station or the planned “Deep Space Gateway” or just “Gateway” as well as further missions to Earth’s moon and Mars. Astronauts are living and working in a uniquely stressful environment. To ensure safe travel and return, it is our duty to protect them from potential hazards and health threats during their adaptation to this new living environment. The first observations gathered during the Apollo missions made it clear that astronauts become more susceptible to infection. The past years of research have identified various immune alterations. The innate system’s central mechanisms such as the generation of reactive oxygen species, phagocytosis, and regulation of the core body temperature become compromised. Yet little can we explain, and nor can we prevent these changes from happening. Nevertheless, it seems evident that maintaining a well-functioning immune system is the prerequisite for space travel. To further expand our knowledge, more research is necessary. We also need to draw information from terrestrial space analog research such as bed rest studies, parabolic flight campaigns, or Antarctic winter-over. Improving the resources aboard for inflight analyses and encouraging reporting of symptoms and disease will help to develop effective countermeasures.
This work has been supported by the DLR on behalf of the Federal Ministry of Economics and Technology (BMWi 50WB0719 and 50WB0919, 50WB1319), the European Space Agency (ESA’s ELIPS 3 and 4 program, and E3P), the Russian Space Agency (Roscosmos), and the program of fundamental research (theme 65.1) of the Institute for Biomedical Problems (IBMP). We explicitly thank all the helping hands, operators, scientists, and administrators at Roscosmos, IBMP, TsNIIMash in Russia, at ESA, CNES, and DLR as well as the NASA Kennedy Space Centre and the Johnsons’ Space Centre, who made this project possible. Our highest appreciation is expressed to the ISS crews who have participated with motivation and who realized these studies with outstanding professionalism.
In honor and memory of Cosmonaut Dr. Boris Morukov former vice director of IBMP and mission director of Mars500 who passed away in 2015.
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