Researchers Examine Immune Cells' Workings
STEVE INSKEEP, host:
Now here's some news about how your immune system responds to a threat. Let's say you've just stepped on a nail. Your nervous system let's you do things like hop up and down or say `Ouch.' Your immune system gets you ready for war. The system's job is to fight off any germs that might have been on that nail when it pierced your skin. A team of scientists at the University of Pittsburgh says that immune cells have an unusual way of communicating with each other when it is time to fight off an invader. Here's NPR's Joe Palca.
JOE PALCA reporting:
What these immune cells do is shoot out tiny tubes, what the scientists call `tunneling nano tubes.'
Mr. SIMON WATKINS (Cell Biologist, University of Pittsburgh School of Medicine): The tubes are absolutely extremely small and we believe that, for the most part, people looking down an ordinary microscope won't see them.
PALCA: Simon Watkins is a cell biologist at the University of Pittsburgh School of Medicine. Watkins isn't the first to see these tubes, but he may be the first to explain what they do. Along with his colleague, Russell Salter, Watkins has evidence that the tubes are for communication following an injury.
Mr. WATKINS: If you imagine you get an infection in your skin and one cell is stimulated and, if that one soldier, if you will, now has to move from, say, the bottom of your foot up to a nearby lymph node, which would behind the knee for example--and that's quite a long way for one cell to go and its likelihood of getting there is very low. So what we think happens is that the cells through the tubes say, `Hey, guys, there's something going on here that shouldn't be going on.' And then a whole host of cells go running off to the lymph node.
PALCA: Once they get to the lymph node, other cells kill off the invading germs. Watkins presents his evidence for communication via these tunneling nano tubes in the latest issue of the journal Immunity.
Immunologist Michael Cahalan at the University of California Irvine say Watkins' theory makes sense given the way the immune system works.
Mr. MICHAEL CAHALAN (Immunologist, University of California Irvine): It's a very touchy-feely system. The cells need to sniff each other and tubules of this sort could make things happen at a distance longer than we previously suspected.
PALCA: So far, this communication has only been demonstrated in a laboratory dish. Daniel Davis is a physicist turned immunologist at Imperial College, London.
MR. DANIEL DAVIS (Immunologist, Imperial College, London): It's still unknown how important this would be where and when these types of connections form in the body, connecting cells, and where or when it is useful for the immune system to use these connections and what we are--what type of information is being transduced between cells over these types of connections.
PALCA: Still, Davis thinks these `tunneling nano tubes' deserve more study and could bring new insights about how the immune system works. Joe Palca, NPR News, Washington.