Researchers at the University of Texas Health Science Center at Houston (UTHealth) Medical School and NASA conducted a test to help explain the phenomenon that some astronauts might have a higher risk of developing infections after their missions.
When the Space Shuttle Atlantis came back from its mission on July 21, 2011, (the mission lasted for 13 days) researchers assessed the immune systems of the mice aboard for experimental purposes and found some alterations that could impair the detection of disease-causing agents. Their findings were published in PLOS One under the title “Post-Spaceflight (STS-135) Mouse Splenocytes Demonstrate Altered Activation Properties and Surface Molecule Expression.”
Scientists also assessed blood samples that were collected from astronauts aboard the orbiter and they found similar alterations in the responsiveness of their immune cells that were triggered because of receptors on the surfaces of cells.
“With deep space missions planned to Mars that could take months, factors contributing to reoccurring and opportunistic infections need to be identified and remedied,” explained Jeffrey Actor, who is a professor of pathology and laboratory medicine at UTHealth Medical School and the study’s senior author.
These modifications could compromise the capacity of the immune system’s phagocytic cells to detect bacteria and other pathogens that cause diseases. “The information uncovered could allow for the design of therapeutic treatments to recover immune function quicker post-flight,” Actor cleared. “Cells involved in immune surveillance use receptors on their cell surface to recognize and respond to microorganisms. Our research suggests that there may be changes to these receptors after a period of weightlessness.”
The study was aimed at investigating white blood cells that were collected taken from the spleens (an organ existent in all vertebrates and its structure is similar to a large lymph node) of mice. Researchers were looking for modifications in both T cells and dendritic cells, that play crucial roles in the pathogens’ immune response.
When researchers compared those mice to others that never left the Earth, some alterations were found. There was a decrease in the markers’ intensity concerning how cells use to respond to their targets.
“Data from this study shed additional light toward molecular mechanisms involved in immune changes induced by spaceflight that could alter activation of innate and adaptive immunity, at least post flight,” explained the authors.