Page 163 - International Space Station Benefits for Humanity, 3rd edition.

Space Station Immunology Insights
for Earth and Space
When people get sick, their immune systems kick into
gear to tell their bodies how to heal. T-cells—white
blood cells that act like tiny generals—order an army
of immune cells to organize and attack the enemy.
Microgravity studies aboard ISS are helping researchers
pinpoint what drives these responses, thereby leading
to future medical treatments on Earth.
Scientists have known since the early days of human
spaceflight that living in microgravity suppresses
the immune system. During the Apollo Program,
for instance, 15 of the 29 astronauts developed an
infection either during or right after flight. Forty years
later, Leukin results show that immunosuppression
begins within the first 60 hours of flight.
Expedition 30 Flight Engineer Andre Kuipers,
Findings from this investigation, led by Millie Hughes- ESA, works with the Kubik facility in the Columbus
Fulford, Ph.D.—a former NASA astronaut and director Module of the ISS.
of the Laboratory of Cell Growth at the University of Image credit: NASA
California, San Francisco—enabled researchers to
pinpoint some specific genetic triggers for the go/no-go
of the immune system responses in the T-cells.
It was the first time scientists have been able to show (i.e., the cell’s protective reaction to initiate healing)
that gravity is making a difference in activation of the occurs. Cells also produce fewer cytokines, which are
T-cell. A healthy body depends on these T-cells to give the proteins responsible for signaling communications
orders for the immune system to function properly as it between cells. A negative impact to a cell’s ability to
marches into battle. However, certain factors such as multiply, known as mitogenesis (i.e., the chromosomal
signal interruption, delayed responses or even outright splitting in a cell nucleus necessary for cell
cell death can hinder victory. A suppressed immune reproduction), also occurs.
system is like an army with an ineffective leader, Examples of immunosuppression on Earth include the
significantly reducing the chances of a successful fight. Acquired Immune Definiciency Syndrome (AIDS)-related
Results revealed that specific genes within T-cells HIV infection, rheumatoid arthritis and even age-related
showed down regulation—a decrease in cell impacts to the immune system, which is why the elderly
response—when exposed to microgravity. have a difficult time fighting off infections such as
This combined down regulation in the genetics of pneumonia. Identifying how the immune system works
T-cells leads to a reduction in the body’s defense at the cellular level provides a powerful tool to develop
against infections during spaceflight in various ways. treatments at the root of the defense response. This is
For instance, a reduced pro-inflammatory response similar to a negotiation for peace talks before conflict
breaks out, instead of trying to raise a white flag in the
midst of an already raging battle. If doctors can isolate
and control specific immune responses, they increase
the chance for recovery. With the removal of gravity
as its own variable, the data gathered from immune
Results revealed that specific studies in space can be used to help understand some
genes within T-cells showed of the immune challenges seen in these populations
down regulation—a decrease in on Earth.

cell response—when exposed Hughes-Fulford launched a follow-on immunology
study aboard the space station. This study was funded
to microgravity. by a grant from the National Institutes of Health and
sponsored by the ISS U.S. National Laboratory (http://
www.iss-casis.org/). T-Cell Activation in Aging,

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