Pinpointing The HIV Reservoir
There's been a breakthrough in the quest for HIV reservoir eradication. In the upcoming issue of Nature Medicine, Canadian and US scientists prove for the first time where HIV hides when it's under attack from anti-retroviral drugs.
HIV remains despite drug therapy
So far, anti-HIV drugs manage to keep HIV at very low levels in the body. But they are unable to get rid of the virus completely. Scientists have been searching for the reservoirs where the virus could hide. Now, they believe they have found them.
So, where is HIV hiding?
As AIDS Research Alliance hypothesized when it first began researching reservoir busting strategies, HIV hides in a cell that can remain in your body for the rest of your life. It's a very important cell in the immune system. This is the kind of cells that are called memory T-cells. They are the cells that carry the memory of seeing an infectious disease.
jWhen a person is vaccinated against a particular disease, these memory T-cells remember how to respond if that pathogen is somehow introduced into the body. They then launch a very specific attack. But, they are also the perfect hiding place for HIV.
Assumptions were wrong
“Everybody went with the assumption that by using more and more potent drugs that target the virus that we were going to be able to get rid of it. And in fact what we found is that that will never work," states Dr. Rafick-Pierre Sékaly of the University of Montreal.
A Different Approach
He says a different approach targeting not the virus, but the cells in which the virus is hiding, is needed to eliminate the virus.
The team of Canadian and U.S. researchers found that treating HIV/AIDS with a combination of antiviral drugs and chemotherapy seems to destroy both the circulating virus and immune cells in which the virus hides.
Their results made them try a strategy similar to the one used against leukemia, which is targeted chemotherapy, associated with a targeted immune treatment. This approach may make it possible to destroy the cells containing a virus while giving the immune system time to regenerate with healthy cells.

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THE HIV LIFE CYCLE
Getting In
Entry of HIV into the cell is a three-step process
- 2 proteins on HIV’s surface (gp120, gp41) bind with molecules (CD4, CCR5, CXCR4) on the surface of the T-cell that act as powerful receptors for HIV, allowing the virus to attach itself.
- The HIV gp120 protein attaches to the T-cell receptor CD4, then the gp41 protein binds to another either CXCR4 or CCR5. Imagine HIV is using one hand (gp120) to grab the doorknob (CD4) and another hand (gp41) to unlock the door (CXCR4/CCR5).
- Once attached, HIV fuses with the cell by piercing its surface and releasing its RNA inside the cell.
Taking Over
Once HIV’s RNA is inside the cell, it undergoes reverse transcription to convert into DNA, the form of genetic information that is recognized by the T-cell with the help of an enzyme called reverse transcriptase.
Next, the new DNA enters the host cell nucleus where it is integrated into the genetic material of the cell with the help of the enzyme integrase.
The new DNA now can either to remain in a dormant – or latent – state inside the cell for many years, forming reservoirs of hidden virus, or
It uses the cell's own machinery of producing proteins to start making viral proteins and RNA needed for another generation of HIV
Putting it Together
When first synthesized by the cell, the viral proteins are joined together forming a large molecule that must be cut down to proper size to make new viruses. The HIV enzyme protease is necessary for this cutting process.
The new viral RNA and proteins are ready to be assembled.
Afterward, the new HIV burst out of the host cell (budding) and invade new cells, continuing the infection.
Unless the HIV lifecycle is interrupted, viral infection spreads throughout the entire body. HIV can make 100 million virus particles each day in patients with fairly advanced HIV disease. When HIV kills enough of T-cells, the body’s immune system can no longer function effectively, and the body is incapable of combating various types of deadly infections and cancers.

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