Millie Hughes-Fulford, PhD, director of the Laboratory of Cell Growth at SFVAMC, scientific advisor to the Under Secretary of the U.S. Department of Veterans Affairs, and a payload specialist aboard space shuttle flight STS-40 in 1991, will send human T-cells up to the International Space Station aboard ISS Soyuz 13. That science mission, operated by the European Space Agency, is scheduled to launch from Baikonur between September 14 and September 18, 2006.
"We're doing this experiment because many astronauts are immunosuppressed during flight. Their T-cells stop working in microgravity," says Hughes-Fulford, who is also an adjunct professor of medicine at the University of California, San Francisco. "This experiment will tell us for the first time exactly which genes involved in the normal immune response aren't activated in space."
T-cells are white blood cells that play a central role in the body's immune response. They are a target of human immunodeficiency virus (HIV), which suppresses them. When an HIV patient's T-cell count falls below 200, he or she is susceptible to the dangerous infections that are the symptoms of acquired immunodeficiency syndrome (AIDS).
The problem of immunosuppression in microgravity was first noted during the Apollo moon mission series in the 1960s and 1970s, when 15 out of 29 Apollo astronauts developed infections during their missions or soon after landing. Subsequent experiments aboard Skylab and several space shuttle missions, including Fulford's, confirmed that T-cells do not activate properly in microgravity.
"In this experiment, we're looking at why they're not working,"
Source:University of California - San Francisco