ウイルスに対する抗体がワクチンに開発に明りをともす
La guerra darwiniana del sida
La forma en que los anticuerpos coevolucionan con el virus ilumina el camino hacia la vacuna
Un paciente africano permite el hallazgo
Javier Sampedro Madrid 3 ABR 2013 - 18:58 CET
AIDS Darwinian War
The way that antibodies to the virus coevolve lights the way to the vaccine
African patient allows finding
Javier Sampedro Madrid 3 ABR 2013 - 18:58 CET
Darwin was unable to know how much their ideas were to illuminate a subject for which there had been conceived: immunology. What happens in the body after infection with a virus like HIV is not very different, in fact, leading evolutionary wars both predators and prey to run faster so that everything remains the same. Ideally, as before the infection. The forefront of research on AIDS vaccine is exploring these gardens thoroughly Darwinian forking paths within the body.
Immunologists know that a small fraction of HIV patients develop broad-spectrum neutralizing antibodies against the virus. Neutralizing called because they are capable of blocking (neutralizing) the virus in laboratory tests with human cells, and are also broad spectrum because they neutralize the AIDS virus other than the one that induced its production in the patient's body. Are, therefore, one type of antibody interesting to explore the clinical application.
Scientists at Duke and Rockefeller universities have analyzed one of the rare people who develop these antibodies neutralizing an African patient detected in the earliest moments after infection. Scientists have focused on finding out how to co-evolve the HIV virus and the patient develops antibodies against it.
Their results, reported in Nature, show that neutralizing antibodies are not the product of a long coexistence of the immune system with the virus, but were already detectable at 14 weeks of infection, and that were created in response to a protein mutant HIV. The virus is fast, but, in these rare patients, so are the antibodies.
"Most vaccines work by inducing an antibody response to this," said Barton Haynes, director of the Human Vaccine Institute at Duke University, and colleagues, "but HIV has proven difficult target to generate a vaccine ". After suffering the infection, all patients generate an antibody response against HIV, but its spectrum is so limited that mutant forms of the virus escaping from his attack immediately. Is the beginning of a Darwinian arms race that in most cases, gains unless HIV antiviral drugs scale load in the opposite direction.
The African patient under study was detected so early that HIV isolated from his blood had not had time to accumulate a single mutation compared to circulating virus. UK to this fortunate circumstance, the fact perceived after the patient belonged to the minority (perhaps 20%) of people who produce neutralizing antibodies against the virus spread spectrum persuaded researchers in their study rollover.
The most encouraging result of this work is the thorough characterization of these antibodies as desirable. Molecules are specialized in attacking vulnerable sites (epitopes in the jargon) in the main protein of the viral envelope (env) that tend to remain stable for long to mutate that gene. Antibodies are much more evil than the vast majority of his colleagues, like good chess player, seem to think several moves away. Whatever you do in the subsequent evolution, the virus is screwed.
This is just the kind of weapon that deserves the tough and elusive enemy. And offers a very concrete target to focus the efforts by a vaccine based on antibodies.
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