Tuesday, February 15, 2005

Staring them in the face

This thread from a dissident discussion group is telling. One person writes:

"If they're able to strip HIV of it's disease-causing components (which sounds like quite a feat), then why the hell can't they create a vaccine?".

A moderator steps in with:

"Well of course all those 'expert scientists' didn't want to bother us with too technical details on how in the world they managed to re-engineer something that no one can seem to find in fresh, uncultured human blood."

No one there seems to be thinking the obvious: maybe they were lied to about how much HIV there is in infected people.

The design of the construct is actually presented in the published paper, available as an online article from Nature. The supplementary figure 1 has the construct map. Engineering HIV is done every day - I've constructed at least 5 unique HIV plasmids and re-engineered several old ones using the designs of previous workers. Removing the pathogenic bits is relatively easy, but then you have a major problem in that the virus effectively dies! You need supportive DNA constructs in order to make more "virus". The safer you make it, the less effective the virus becomes: and judging from the maps they ripped the guts out of HIV. Practically the only stuff left is the regulatory regions and those structures involved in packaging and efficient gene insertion. There are no antigenic regions that I can obviously see, so this kind of approach is actually the exact opposite of what you would do to create a vaccine!

As for how much HIV there is - that all depends on how much you want there to be. If you don't have a pathogenic organism, then likely you won't have the problem of the virus hiding away in the lymph nodes. Despite that, in AIDS patients Ho et al found enough virus in a single cc of blood to seed 3,500 virus cultures. Most of that was from infected cells rather than cell-free virus, but it still highlights the amount of HIV in the body.

None of this is new, or unusual, or breaks any "rules" of genetics or virology. Why it is denied by the dissidents is difficult to understand.


Blogger Bennett said...

My old lab was a gene vector place: one student prior to me even managed to get HIV-2 to trans-package, which is something it can't do in the natural state. My Prof wrote a review on the field back in 2000!

Curr Opin Mol Ther. 2000 Oct;2(5):488-96.

Lentiviral vectors: progress and potential.

Lever AM.

8:10 AM  

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