Walking with white blood cells described in an article in Science Daily 4 May 2009. White blood cells use the blood circulation system to transport them to sites of tissue damage and infection, but the cells then need to move out of the blood vessels in order to do their work. To get out of the blood vessels they “walk” along the inner surface looking for signs that this is the right place to push their way through the vessel wall.
It was always assumed that the cells moved amoebae-like– extruding a part of the cell in front then folding up and dragging the rest of the cell along. Immunologists Ronen Alon and Ziv Shulman of the Weizmann Institute, Israel have studied this process more closely and found that white blood cells form lots of small extrusions, about one micron in length and move along like millipedes. These tiny temporary legs are covered with adhesion molecules that bind to partner adhesion molecules present on the surface of the blood vessels. The legs embed themselves in the surface of the cells lining the vessel wall enabling the white cells to get a good grip so they can move forward and also serve as probes looking for the exit signs on the vessel wall.
The researchers also found that the force of the blood flowing over the cell is necessary for the process to work. Without it the white cells are unable to grip the vessel wall and sense the signals from the damaged tissue where they need to move through the vessel wall. It seems the sheer force of flowing blood causes the adhesion molecules to enter highly active states and without it the white blood cells couldn’t sense the exit signals or get to the site of the injury.
The scientists are hoping that understanding white cell movement will enable them to develop methods of controlling over-aggressive white cell activity that occurs in auto-immune diseases.
Editorial Comment: Notice how many things are needed for this system to work – the flow of blood, the millipede legs with adhesion molecules, the vessel wall cells with complementary adhesion molecules, the exit signalling molecules at the site of injury, and that is just to get the cell to the site of its work. Intelligent human scientists are just beginning to understand how intelligently designed this system is, and it will take more creative intelligence to modify the system so we can use it for what we want.
Creation Research predicts that the reason it sometimes goes wrong will be found to be a degenerate loss of a normal control, which fits with the history of the world beginning with a very good creation followed by degeneration, as described in Genesis 1- 3. (Ref. design, haematology, immunity, immunology)
Evidence News 24 June 2009