Word: proteins
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...trying to figure out exactly why the immune system attacks the beta cells. Last October a Stanford University team discovered errant forms of a gene that controls the development and growth of the culprit T cells. The team's conjecture: in Type 1 diabetics, this gene produces a protein badge that differs slightly from the norm in structure, causing the immune system to attack the beta cells. Eventually, the group hopes to find a way to neutralize the harmful effects of the molecule and thus eliminate the need for immune suppressants like cyclosporine...
...virus, the macrophage, which moves about, amoeba-like, on long cellular extensions known as pseudopods (false feet), does more than just ingest the intruder. It has another, even more important function. On its surface, like virtually all body cells, the macrophage carries MHC (for major histocompatibility complex) molecules, protein badges that enable other immune cells to recognize the macrophage as friend, or self, and not attack it. After digesting the virus, the macrophage proudly displays strips of protein from the virus in the grooves of some of its MHC molecules. Once a bit of protein -- which is part...
...killer T cells are relentless. Docking with infected cells, they shoot lethal proteins at the cell membrane. Holes form where the protein molecules hit, and the cell, dying, leaks out its insides. To ensure that the cell and its viral occupants are destroyed, the killer T cells then deliver the coup de grace by transmitting a signal that causes the cell to chew up DNA from both itself and the virus. Explains Dr. Irving Weissman of Stanford: "This is an overlapping, dual system of killing that ensures that the seed of viral production will be eliminated from the body...
These days the explosive growth of both molecular biology and immunology has enabled vaccine makers to take a safer and more effective approach to their work. Instead of using dead or attenuated bacteria or viruses, they remove from the bug's surface the marker protein, or antigen, that provokes the immune response. Employing gene-splicing techniques, they mass-produce the antigen, or a portion of it, and use it as the prime ingredient of the vaccine...
Allergy sufferers are now treated with antihistamines, which temporarily block the immune response, as well as steroid nasal sprays and inhalers, which reduce inflammation. But more effective help may be on the way. Scientists have synthesized bits of protein molecules that prevent immunoglobulin E antibodies from setting off an allergic reaction...