Abstract
The immune system is one of the systems most affected in microgravity and during space flight. Substantial research and development activities are required in order to provide basic knowledge for appropriate risk management, including efficient countermeasures. The special sensitivity of immune system cells to altered gravity makes them an ideal model system to understand how gravity on Earth is required for normal mammalian cell function and signal transduction. As a direct result of reduced gravity, many studies have confirmed alterations in the molecular mechanisms and signal transduction processes in immune system cells - including the monocyte-macrophage system (MMS). The MMS belongs to the innate immune system and represents the body’s first line of defense. The MMS is characterized by a fast, but unspecific immune reaction, and it activates the adaptive immune response. Given the extremely complex nature of cellular signal transduction networks, any observed effect in altered gravity could be secondary, adaptive, or driven by negative or positive feedback-loops, and thus far beyond the initial and primary cellular response. Therefore, coordinated in vitro studies with living human cells of the MMS in microgravity conditions, such as experiments on board parabolic flights, suborbital or orbital flights, and ground-based devices for simulated microgravity, provide suitable platforms to elucidate the underlying cellular and molecular mechanisms. They also help to clarify whether and to which extent gravity is involved in normal cell function or how cell function is impaired by altered gravity. We present technological developments for the investigation of the MMS in microgravity and space, in a coordinated research approach. Whereas the technology is often customized to the scientific project and just for singular applications, key components and key functions are usually patented.
Keywords: Macrophages, innate immunity, microgravity, gravisensitivity, space flight.
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