Control of the life cycle of the HIV virus

Control of the life cycle of the HIV virus
I am now going to tell you how to control the life cycle of the HIV virus. Comment fig p1257, Science Review. I am using this complex figure to make my point but I do not expect you to memorize everything. I want to show you that there are indeed several ways to control the life cycle of the HIV virus, that scientists are making a lot of progress and that an ideal treatment would be the combination of several drugs that act at different levels in the life cycle to increase the chance of controlling efficiently the life cycle.

This figure is divided in 3 parts. The central part is a schematic of the life cycle. On the left are mentioned the different steps in the cycle with numbers. On the right are mentioned the different drugs that interfere with the cycle with corresponding numbers. You can see that for each step, there is one or several corresponding drugs. This is a very optimistic statement. I am now going to focus on the drugs currently used in therapeutics today.

1. The most common drug used is AZT (ziduvidine). This molecule acts at the reverse transcription step when the single stranded viral RNA molecule is copied into a DNA molecule by the viral reverse transcriptase. The AZT is a nucleotide mimic, it incorporates into the DNA during the process of reverse transcription. Then, the reverse transcriptase is not able anymore to go further in the process of the DNA molecule elongation. The result is a stop of the reverse transcription. No DNA synthesized, no new viruses released into the blood. There are also 2 others similar drugs used in therapeutics: ddI and ddC. I do not want to sound pessimistic but the sad reality is that these drugs are poorly effective and not represent a major hope. The paradox is these drugs is that there are more efficient during the terminal phase than during the asymptomatic phase. It is why scientists had developed an other type of drug.
2. Inhibitors of viral protease. You may have heard about them because the CNN channel made them public a month ago. At the end of the life cycle of the virus, viral proteins are synthesized from the mRNA. The first proteins to be synthesized are longer than required in their final forms. The protease cut them in smaller, functional proteins able to form a new virus. If this cutting process is inhibited, the new viral particle is malformed and then noninfectious. This approach seems to be very promisive.

But once again, the ideal scenario would be to find the perfect combination of drugs in order to control the life cycle at different stages and then increase the chances of interfering with the formation of new viruses. Mention soluble CD4