Slashdot Mirror
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."
I spent many years in medical school doing research work on viruses, including work with SIV. This article is very optimistic in some of its summaries. HIV and SIV are qualitatively different in the extent of "hypervariability" in their surface proteins. It is generally accepted to be "easier" to create antibodies to SIV, which has been done for many years.
http://www.ncbi.nlm.nih.gov/pubmed/7865316?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=1&log$=relatedarticles&logdbfrom=pubmed
The technique described is very interesting, don't get me wrong, and I hope it works. However, there are *already* many techniques that appear to immunize against this HIV analog, which do not work for human HIV. The two are significantly different.
Slashdotter, ID #101. UIDs are in binary, right?
You mean SIV NEGATIVE monkeys who are engaging in unsafe behaviors (unprotected monkey sex, sharing heroin needles, and participating in HIV related research as test subjects.) Vaccines usually don't cure you once infected (rabies is a limited exception), I suppose this one might, but so far it's only been demonstrated to prevent infection, not eliminate after infection.
Injecting the antibodies directly does neutralize the virus, but unfortunately, the body's immune system recognizes those antibodies as foreign and so mounts an immune response against them (an anti-antibody antibody, if you like), which clears them from the bloodstream. So you'd need regular injections of neutralizing antibodies to maintain a therapeutic concentration in your blood. To quote the paper: "Passive immunization schemes using neutralizing antibodies have protected monkeys from SIV or simian-human immunodeficiency virus (SHIV) challenge infections. Unfortunately, an injection of antibodies every few weeks is neither practical nor cost effective as a large-scale human vaccine approach."
Indeed, sadly enough. Last time just 2 months ago, on his way to Africa precisely...
We might be one step closer to a vaccine, great news. In the meantime, someone please tell the Pope that condoms do save lives?