Cell Wars

Imagine two balloons, he says. "If you put them side by side, and pressed them together, the surface area that's in contact can be quite large." But, he says, if you have two bowling balls, no matter how hard you press them together, only a tiny fraction of their surfaces will meet. Such cells have less ability to exchange the chemical signals that command them to go into action

It's still unclear what these findings mean for the health of space travelers. Astronauts do show an increase in virus levels. For example, notes Duane Pierson, head of microbiology for the Johnson Space Centre, when astronauts cough or sneeze, the droplets released contain 8 to 10 times more of the common Epstein-Barr virus (which causes infectious mononucleosis) than normal Earth sneezes. Although that's an indication of immune system suppression, the astronauts themselves have remained completely without symptoms.

Nor is it yet clear exactly what keeps T-cells round. Without the usual effects of gravity, explains Pellis, other forces --perhaps intermolecular or submolecular forces, such as hydrogen bonding -- must play a larger role, so that in microgravity, these other forces control the shape that the cell takes. "But exactly which forces are doing what to whom, where and how, to arrive at a spherical cell, I don't think anybody knows.”

Finding out is important ... and not only for astronauts. This research will also help people on Earth.

T-cells protect us from all kinds of problems, says Pellis, but they don't always behave as we would like. "There are times when we don't want them to invade -- transplants, for example. And there are cases when we want them to act vigorously, like in tumours."

Understanding the way physical forces affect T-cells could eventually allow scientists to control them -- "taming" them so that they help us, as they're meant to, in far more effective ways.