Gene Transfer Immunizes Against Monkey HIV Analog

Al writes "Researchers at the University of Pennsylvania have immunized monkeys against the simian immunodeficiency virus, the animal model that is closest to HIV. They did so by shuttling a gene into the monkeys' muscles, making the muscle cells produce antibody-like molecules that work against SIV. With both SIV and HIV, the chameleon-like mutability of the virus's surface changes so quickly that most antibodies made by the immune system are soon rendered ineffective. Philip Johnson and colleagues designed DNA sequences for two antibodies known to be effective against SIV. They used antibody-like molecules, called immunoadhesins, in which the functional part of an antibody is fused with a more stable section of another antibody. The same approach could be used to deliver antibodies that are effective against HIV, but which the body doesn't normally produce."

Don't virii evolve extremely quickly?

[Anonymous Coward]

It would seem to me like this would maybe work for a year or so, and then there'd be some new strain that these antibodies might not hit.

Re:Don't virii evolve extremely quickly?

[Shoe Puppet]

I imagine once a working immunization exists, it can be adapted to new strains when needed.

End run around non-protective responses

[Guppy]

I'm kind of seeing this technique as an end-run around the "decoy" problem. It's been well known for some time that, at least in the general population, the antibody response against HIV tends to get targeted towards features which are non-protective or hyper-mutable.

However, over time we've come to discover a very small number of patients who have unusual resistance to progression. Some of these possess receptor mutations, some have unusual HLA types, while others were merely infected with what appeared to be somewhat milder variants of the virus.

However, in a few rare cases, we discovered patients with antibodies that were unusually effective at dealing with HIV's evasions. Often these antibodies had "weird" features -- things like floppy sections of their variable regions that allowed them to reach down to contact hidden epitopes, and other rare features. While they offered hope that an effective antibody response was not impossible, at the same time there really much chance of designing an antigen in such a way to get the general population to produce these unusual variants.

So, what this work has apparently done, is skip the entire vaccination step. Clone out the sequence for those particularly effective antibody variants, get your target organism to express them directly. However HIV may adapt to the new antibodies, as long as you can find one single person, somewhere in the world with an effective antibody response, it can be duplicated elsewhere.

Re:Don't virii evolve extremely quickly?

[moderatorrater]

Maybe, but at the same time if it works 80% of the time, then the infection rate will go down much further than that and stop the problem almost in its tracks. If another strain comes out that can get around it, then we've still got existing medications and the ability to adapt the shot to the new strain.

What would be best is if the treatment is cheap enough to administer in Africa (and if it's really effective, than that can be relative since I can see a lot of people and countries giving more money for something this big). Stopping AIDS in Africa could easily be the biggest medical achievement this century.

Even more interesting HIV news

[Dr. Manhattan]

A gene therapy in humans that reawakens a gene we lost [scienceblogs.com]. The kicker? A kind of antibiotic cream can reawaken it without gene therapy!

Re:Don't virii evolve extremely quickly?

[geekoid]

Good luck with that.
You are talking about a continent where fuck twads A.K.A. Anit-vaccines and woo crowd, have the governments convinced that vaccine are a western evil and the one should use natural remedies, like beating them selves with certain type of plants.
Hell some places spread the lies that condoms are a western evil.
Many Islam areas in Africa claims it's all the woman's fault. Of course, they also won't let the women do anything about it, like use a condom.

Fuck. twads.

Re:Don't virii evolve extremely quickly?

[Locke2005]

Worse than that -- some Africans believe that AIDS can be cured by having sex with a virgin. A belief not exactly compatible with halting the spread of the disease. The most effective immunization against HIV is information and education of the entire population. Antivirals don't cure the disease, but they can certainly prevent the taker from infecting others if used in accordance with doctor's orders.

Re:Don't virii evolve extremely quickly?

[DJRumpy]

That is a common mistake. They state right on the bottle that they do not prevent infection. They reduce the viral load to undetectable levels (beneath the test threshold) but they do not eliminate the virus and they do not prevent infection. There are people who are exposed to the virus who will take a sort of day after regimen to hopefully prevent infection but it's not proven to work (how would you ever get test subjects to agree?)

This advance is interesting in that it causes the body to produce an antibody permanently via synthetic means. Much like taking an antibiotic pill for a few weeks. I have to wonder if/when the body would stop producing antibodies or if it would continually produce them for the remainder of the recipients life.