|MadSci Network: Immunology|
Pigeon - This is a very good question that you asked. To the best of my knowledge (and from a literature search), we don't know exactly how it works. There is a lot of interesting work currently being done to understand more about the human immune system as a whole. I can tell you what I do know about Vitamin C and where it is needed in the immune system. One known function of Vitamin C in the immune system is aiding in the killing power of neutrophils. Neutrophils are cells involved in the "first line of defense" of the immune system. Netrophils will engulf (eat) harmful bacteria and viruses in an effort to stop an infection. Once the neutrophils have engulfed any of the above, they use powerful oxidation reactions to kill or inactivate these agents. Studies have shown that Vitamin C increases the killing power of neutrophils; therefore, making the immune system stronger in a sense. Vitamin C (also known as ascorbic acid) is sometimes referred to as an "antioxidant" or a "sequesterant". Antioxidant means that it can inhibit oxidation reactions. In the body, oxidation reactions can be quite harmful, leading to the damage of cells and DNA. We don't know if Vitamin C acts to slow or stop these reactions. The body does have other effective systems built in to stop these reactions. Its sequestering properties, or ability to "chelate" (tie up) certain metal ions may also play an important role. There are many metals that are important for many forms of life including humans, animals, bacteria, etc. Therefore, the body has mechanisms to keep a strong hold on these metals. At the same time, harmful bacteria which may cause infections, also have mechanisms to take these metal ions from the body. Again, we don't know if Vitamin C acts in the body by "tieing up" metal ions. All of the functions that I have mentioned may be important for the immune system to function effeciently. In any case, it is important to get your RDA of Vitamin C and other nutrients to be healthy. The immune system is a very complex and very interesting subject. I hope that what I have told you helped. Maybe as you continue your studies into high school and college, more facts will be known about how Vitamin C works in the immune system! - Glynis Graduate Student/Food Microbiology
Try the links in the MadSci Library for more information on Immunology.