Merck's AIDS vaccine fails, trials halted

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5 pointsjyrzyk3 comments

Does anyone know the details of how this particular vaccine worked? The problem is that most companies are STILL approaching it as though it's a traditional virus like chicken pox. HIV-1 has a defective DNA polymerase, so everytime it replicates it introduces errors/mutations. This is why it changes so quickly.

Most of these vaccines try to get the body to produce antibodies that recognize the envelope protein. The envelope protein though is free to mutate without changing the action of the virus. People who somehow naturally produce antibodies making them immune to HIV have antibodies that target the active sites of gp120 or gp41. In other words, they need to mimic the receptor that HIV binds to in order to enter the cell. This area CANNOT mutate or else HIV will cease to be infectious.

There are problems tricking the body into producing one particular antibody (it's complicated, but it's based on how antibodies are generated). Therefore, I think synthetic antibodies should be mass produced and injected. These will target HIV-1 for destruction while also preventing it from being able to infect CD4+ cells. The problem with this is that producing mass quantities of antibodies is still very expensive.

Will the immune system accept a foreign antibody?

It depends. I would think that as long as the antibody is human, it SHOULD recognize it. If it doesn't, there is no harm, it won't cause an allergic reaction or anything. However, by targeting this region, the binding of the antibody prevents the HIV from binding to the CD4 receptors. So even if the immune system doesn't recognize it, it still disables the virus.

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