A tunneling nanotube (TNT) or membrane nanotube is a term that has been applied to protrusions that extend from the plasma membrane which enable different animal cells to touch over long distances, sometimes over 100 μm between T cells. Two types of structures have been called nanotubes. The first type are less than 0.7 micrometers in diameter, contain actin and carry portions of plasma membrane between cells in both directions. The second type are larger (>0.7 μm), contain both actin and microtubules, and can carry components of the cytoplasm such as vesicles and organelles between cells, including whole mitochondria. The diameter of TNTs ranges from 50 to 200 nm and they can reach lengths of several cell diameters. These structures may be involved in cell-to-cell communication, transfer