How does the Chinese AIDS vaccine that is being tested work

Factual Questions
1

http://www.wpherald.com/print.php?StoryID=20050514-095940-5775r

The AIDS vaccine consists of two gene vaccines, one containing DNA of the AIDS virus and the other carrying poxvirus. The volunteers will receive the poxvirus vaccine in three months, said Wang Youchun, director of the cell laboratory under the Institute for the Control of Drugs and Biological Products.
I don’t really get what this means. Is the DNA of AIDS static? Why would the DNA vaccinate against AIDS instead of the antigens?

2

It’s hooey. The PRC has a lot of problems in the Health field.

Yes, HIV shows a huge amount of variation. Among different types, there can be a 50% difference in DNA. Within a type, you can get 25% variation. Compare to humans and bonobos who share over 99% DNA. Then, once you get infected, the viruses in your body start mutating to outrun your immune system. I.e., it’s one mutating motha’.

The main search for a vaccine focuses on finding a stable shell protein that can have antigens created to attach to and will also disable the virus without also attacking the person. No luck so far.

3

What makes you say its all hooey?

http://www.chinaembassy.org.ro/rom/kjwh/t177688.htm

Chinese researchers began to study AIDS virus strains and their membrane and core proteins in 1996. The 8-year study indicates that the two-step vaccination, namely DNA vaccine plus mediated virus vaccine, can produce an immunity to AIDS in human body, without being infected after the vaccination. Researchers injected the vaccine into monkey’s body, and then launched an attack using AIDS viruses. No abnormal response was observed.

And its not like they’d just start human testing w/o doing alot of animal tests and research before that point.
And even though there may not be a stable antigen on the HIV molecule, HIV molecules enter through the CCR-5 receptor, and individuals with mutated CCR-5 receptors do not get AIDS (as far as I know).

Supposedly smallpox vaccines http://www.medicalnewstoday.com/medicalnews.php?newsid=4288

reduce the risk of getting HIV by 400% because that vaccine involves the CCR-5 receptor too.

Of course if that were really reliable you’d assume smallpox vaccines would be used for that purpose.

4

Smallpox is hellava more contagous than HIV–isn’t this risky? :confused: :dubious:

5

Um, forgive me if I’m wrong, but I believe that HIV is a retrovirus, and has no DNA. It has RNA only. This, I think, is why it mutates so easily, and why it is so hard to produce a vaccine for it.

6

HIV mutates so easily for three reasons that I can think of (feel free to correct me if you’re an HIV expert):

  1. HIV reverse transcriptase, the enzyme that turns HIV’s RNA genome into DNA, has a high mutation rate.
  2. The surface proteins of HIV have a lot of… I don’t know if there’s a technical term, but basically “fluff.” They have regions that can mutate to virtually anything without affecting the infectivity of HIV, so there’s very little selection against mutation.
  3. HIV produces many, many, many copies of itself within each cell, so even if only a tiny percentage of those are functional, it still survives.

The “DNA of the AIDS virus” in the OP would be the DNA form of the AIDS RNA (they’re interconvertible). I don’t know know enough about this particular vaccine to say whether it could work, but the terms they use aren’t enough to rule it out.

7

I’m just not sure how it works. Is there some static antigen on HIV that the Chinese have found? Are they blocking off the CCR-5 receptor to prevent HIV from infecting cells, or is there some other method for how this vaccine works?