This is a very complex subject so I will try to simplify as much as possible. If you remember, several weeks ago I described how the HIV virus infects a human cell. First, it attaches to the susceptible cell (usually the immune cells) via areas called receptors, and then, it injects its chemicals and genetic material into the cell.{{more}} The chemicals âtake overâ the host cell in a kind of a siege and control the engine of the cell. The viral genetic material (called RNA) is then replicated to make genetic material that looks like the host cellâs material (called DNA) by a special viral enzyme called reverse transcriptase (remember that strange word!). In other words, it reverse transcribes (or writes the genetic code backward) to make DNA from RNA. The viral DNA is then incorporated into the native cellâs DNA, so the cell does not even recognize that it is the viral DNA, since it is now part of its own genetic material. In other words, the virus has really taken over the cellâs engine and is now behaving as though it is at home. It reminds me of thieves who break into your house and make themselves at home, by eating your food and even washing up the dishes before leaving with your valuables!
The virus then uses the cellsâ own engine to make more copies of itself, but not the DNA copies, but the RNA, because the HIV virus is a RNA virus.
To recap, the HIV virus goes into the cell as a left-handed gene virus. It then makes a right-handed copy of itself, which it then incorporates into the cellâs own genes, which are right-handed. It then makes left-handed copies of itself, using the right-handed template, because the cells machine can only use the right hand template to either make right-handed templates for itself or left-handed templates for the virus. This left-handed template is then repackaged and transported out of the cell to cause more damage, because the cells are destroyed in the process. Obviously, the virus could have just made copies of itself without being incorporated into the cellâs own DNA, some will say. In other words just make left-handed copies of itself from scratch. The problem is, it would be a slow process. Why not just take over the factory and make more copies by carrying what is essentially needed to take over the factory. Besides, if the virus sets up its own factory, the body will recognize it and try to destroy it. By taking over the cellâs own factory it âhidesâ from the cellâs destruction mechanism. Remember I said that if the cell recognizes something is wrong with its genetic material it tries to repair it or it destroys itself (i.e. it commits suicide). Imagine the viral particles infecting a person as a small band of special forces, lightly armed, but whose weapons are very effective. They quickly subdue and take over the enemiesâ camp, and then they camouflage themselves to avoid detection, while they kill the troops inside the camp.
The types of drugs or medications used to treat HIV can therefore be classified as:
1. Those that prevent entry of the virus into the body by any means, called entry inhibitors.
2. Those that specifically block the door or the area where the virus attaches to the cell (called the receptor). These are called receptor blockers.
3. Those that block the enzyme or substance that allows the virus to make a right-hand copy of itself. The enzyme is called reverse transcriptase and the medications are called reverse transcriptase inhibitors. This class of medication is very important, because it is the mainstay of treatment. It attempts to stop the virus camouflaging itself.
4. Protease inhibitors: these medications stop the virus from assembling itself for export, by blocking the assembly line.
5. Integrase inhibitors attempt to stop the right-handed DNA made from the virus left hand from becoming part of the native DNA i.e. tries to stop camouflaging.
6. Maturation inhibitors: these medications stop the viral particles from maturing, by preventing the shell of the virus from being formed properly so the virus is defective.
Next week, I will discuss the benefits of treatment.
For comments or question contact:
Dr. Rohan Deshong
Tel: (784) 456-2785
email: deshong@vincysurf.com
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