What new knowledge concerning the immune system has been discovered by AIDS research, and how will this benefit sufferers of other illnesses?
There are many different cells which work to help defend the body from invaders. The first immune cells discovered were antibodies and macrophages. Antibodies play a key role, that of neutralizing foreign substances, especially viruses. Each antibody recognizes and attacks a certain 'enemy' substance. Macrophages work as the 'cleaning crew' of the cell, consuming dead cells, and foreign substances. Later, the T cells were discovered. One type of T cell, the Killer T cell destroys cells that have been infected.
The blood contains 100 million different types of T cells, each set to act on one particular foreign substance. Each helper T cell contains a T cell receptor molecule which recognizes the substance. When the helper T cell recognizes its substance, it produces killer T cells which destroy the cell which is infected with the substance.
To help the T cell to identify its foreign substance, most cells in the body contain a major histocompatibility complex (MHC) molecule. This molecule allows T cells to recognize infected cells. When the T cell detects an antigen, the T cell recognizes it as an infected cell, and destroys it.
T cells not only ravage seek to destroy harmful bacteria and viruses, but they also attack other foreign tissue. This is why transplanted organs and skin grafts are often rejected. Without drugs to halt the immune system's rapid attack on the tissue, the body would destroy its 'life-saving' implantation.
T cells also are the cause of some diseases, such as multiple sclerosis. In this disease, T cells attack the coating of nerve cells (the myelin sheath). Nerve cells that have had their coating removed cannot conduct the nerve impulses properly, thus causing the person to lose control of his body.
To help fight diseases, such as advanced kidney cancer and melanoma, T cells are extracted from the body. Then, they are multiplied in the lab, and injected back into the tumor. This will increase the body's ability to fight the tumor.
This article included a drawing detailing how the cells of the immune system worked together. It displayed the different cells, and how they interacted with each other to fight oncoming viruses. It also contained a key which contained brief descriptions of the immune system cells. The drawing provided a quick visualization of the contents of the article, and more greatly detailed the sequence of steps taken in the immune system. It also provided a reference source which helped to explain terms used in the article.
The answers questions about the immune system as we know it today, but it does pose a great number of more questions about what we can learn about it in the future. A method for fighting AIDS has still not been discovered, and many more questions must needs be asked before a cure for it, and other immune diseases will be found.