Scientists Witness How Immune Cells Invade Brain In MS

Nerve CellScientists from the Max Planck Institute of Neurobiology, the University Medical Center Gottingen and other institutes have recently witnessed live how aggressive cells from the immune system invade brain tissue and cause considerable damage such as what happens to people suffering from MS.

For so many years, scientists were puzzled just how these immune cells are able to escape the bloodstream and infiltrate the brain, considering that there are specialized blood vessels that act as a barrier between the bloodstream and the nervous system.

The team of researchers has discovered several new behavioral traits of immune cells. The nervous system is composed mainly of the brain and the spinal cord which monitors and controls all the functions of the different parts and tries to coordinate how they work together. Because of this, the nervous system has to be well protected against outside influences that might affect its important function.

The cranial bone and the vertebral column provide the protection against physical injuries. Dangers that lurk within the body such as viruses from the blood stream are prevented from invading the nervous system by a number of highly specialized blood vessels that act as a barrier protecting the delicate nerve cells.

In diseases such as multiple sclerosis however, immune cells become aggressive and break into this blood vessel barrier. After invading the brain tissue it attacks the nerve cells and causes inflammatory reactions as well as debilitating symptoms.

The scientists used a two-photon microscope to trace the movements of aggressive T-cells in the living tissue of rats. The systematic observation of the movement of the said cells during the course of MS provided new discoveries on how the cells behave. What the scientists were able to witness is that T-cells in MS actually creeps, a type of cell movement that goes against the flow of the bloodstream. This behavior is previously unheard of in T-cells.

As some of the T-cells creep along the vessel wall, some eventually are swept away by the blood stream while some are able to penetrate through the vascular wall. Once penetrating the blood vessel barrier, the T-cells then pair up with phagocytic cells which are found in abundance in the outer lining of the vessel walls and on the surface of the nerve tissues. Once the T-cells make contact, they are then immune-activated. And because of this, more and more T-cells pass through the vascular walls and begin to launch an attack on the nerve cells.

Because of the new observations, scientists have a better understanding how the immune cells move and pass through the blood vessel barrier. But there are still other questions that may be brought up by the new insight which will involve further study. Through this and other future studies, the scientists are hoping to find and develop new forms of therapy to treat multiple sclerosis and other similar diseases.

Source: Max-Planck-Gesellschaft. "How Aggressive Cells Invade The Brain: Real-Time Observation Sheds New Light On Multiple Sclerosis." ScienceDaily 6 November 2009. 2 February 2010