The image comes from the research of a team of biologists from several U.S. institutions. Observations of astronauts and studies done in human immune cells have shown that space weakens the immune system. This U.S. team wanted to learn more about what was happening at a cellular level. Their little spacefaring flies taught them that low gravity shuts off an important component of the fly immune system—one that has a human counterpart.
Their findings gave them some starting ideas about why people also have compromised immunity after spending time in space, they wrote in a paper they published today in the journal PLOS ONE. One experiment they performed in hypergravity—created for the flies using a centrifuge in a lab on Earth—also suggested exposure to gravity could prevent the immune effects of space.