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.
Macrophages, innate immunity, microgravity, gravisensitivity, space flight.
Institute of Anatomy, Faculty of Medicine, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.