What is special about HIV that makes it unbeatable?

[wasteofo2]

Why is it that with many viruses the human body can make specific cells that can destroy the virus completely, but not with HIV?

 

[kreil]

white blood cells recognize an intruder virus by its receptor proteins. With most viruses, after a while the body learns it is a threat goes about disposing of it. But with HIV, every time the body tries to attack it, it mutates, and since the body doesn't recognize it as a danger anymore (since there are different proteins) it leaves it alone. In the process, the HIV is destroying white blood cells, making the bodies job even more difficult. The ultimate result is that your immune system is left in tatters, by which time you have aids.

 

[wasteofo2]

That was simpler than I expected, thanks.

Are there any other viruses that do this, or is it just HIV?

 

[bross7]

I cannot think of any off hand that pertain to humans but there are several similar viruses found in primate species that act the same way, hence the ape-human transition belief?
HIV-1 is extremely similar to SIV in Chimpanzee's. Somebody would know a whole heck of a lot more than me on the similaritiest between these two viruses.

 

[garytse86]

Mutations cause changes in amino acid sequence, and they are responsible for synthesis of proteins, the epitope is now different structually, and so the antibody does not recognise the antigen.

 

[Moonbear]

Why is it that with many viruses the human body can make specific cells that can destroy the virus completely, but not with HIV?

HIV attacks the very cells needed to destroy it, and needed to fight off the other opportunistic infections characteristic of AIDS. There are other viruses, such as in the Herpes family (including chicken pox) that are not eliminated from the body once it is infected, but remain latent. You may never get sick from them again, or you might get sick often.

 

[kalladin]

I just read a really interesting article on HIV in my genetics class. It was a paper published in Nature, and the scientists discovered a gene called TRIM5 in humans that tag HIV capsid proteins for destruction (hence preventing infection). But the thing is.. that in humans, we have a CypA gene that encodes for a protein that blocks the receptor on the viral capsid, blocking its interaction with the TRIM5 product. Well the scientists did this experiment or found something.. where the CypA gene was fused to the end of the TRIM5 gene, and apparently, having that gene confers resistance to the HIV virion.

Correct me if I'm wrong, I'm not very good at interpretting papers.

K.

 

[Moonbear]

I just read a really interesting article on HIV in my genetics class. It was a paper published in Nature, and the scientists discovered a gene called TRIM5 in humans that tag HIV capsid proteins for destruction (hence preventing infection). But the thing is.. that in humans, we have a CypA gene that encodes for a protein that blocks the receptor on the viral capsid, blocking its interaction with the TRIM5 product. Well the scientists did this experiment or found something.. where the CypA gene was fused to the end of the TRIM5 gene, and apparently, having that gene confers resistance to the HIV virion.

Correct me if I'm wrong, I'm not very good at interpretting papers.

K.

We can't correct your interpretation unless you cite the paper. Slick move.

Are CypA and TRIM5 ever found together in vivo? Or was this just one of those fusion proteins that has no relevance to what actually happens in the animal? I've seen some bizarre stuff done in the name of molecular biology. Seriously, that's a question to ask yourself when reading papers; is this relevant to what really happens in the animal? And if you can't get the answer from that paper, you have to dig back to another and another paper. Before you know it, you'll be an expert on CypA and TRIM5.

 

[loseyourname]

Just a note, but HIV is not unbeatable. It cannot be eradicated from an infected person, but a given person can be immune to its effects. This was found out in the well-known case of Stephen Crohn, who survived infection without any ill effects. A mutation passed down from survivors of the black plague renders ineffective the gene coding for the CCR-5 protein in those who have the mutation. This is the protein that the HIV virus recognizes and uses to enter human lymphocytes. If the person doesn't have this protein, then he is impervious to the virus. Whether or not this mutation can be introduced into a person that isn't born with it, and thus be used as a form of treatment, is another question.