Scientist Discover New Immune Mechanism

Immune cells use an extensive system of tiny tunnels to deliver signals to distant cells, scientists report. The discovery of this previously unknown cellular communication mechanism may explain why the immune system can respond so quickly to threats, and proves that cells other than neurons can communicate over long distances. Researchers at the University of Pittsburgh School of Medicine found that blood-derived dendritic cells and macrophages -- both antigen-presenting immune system cells -- make use of these tunneling "nanotubes" to relay molecular messages. Using these tiny tunnels, the cells send waves of calcium and other small molecules to cells hundreds of micrometers away. The nanotubes are just 35 and 200 nanometers wide -- 5,000 times smaller than the width of a human hair. At any given time, cells may have up to 75 of these nanotube extensions, of varying lengths.