for those who are not afraid of the future : http://www.rael.org
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National Institute of Health (NIH) scientists have found three new antibodies that neutralize a broad range of HIV strains, increasing the possibility of an HIV vaccine being developed.
Although not rare, the majority of HIV antibodies have a limited range of neutralization because they target the virus at sections that mutate to adapt to its hosts' immune system of its host, which seeks to develop effective antibodies. Until last year, the most effective antibody could only neutralize about 40% of known strains of the HIV virus.
NIH researchers have discovered three new antibodies that neutralize a broad range of HIV strains. This image represents the structure of the most effective antibody, VRC01.
The site of vulnerability was first described in 2007, when NIH researchers from the Vaccine Research Center (VRC) made the cover of Nature announcing their prediction of a site that was common to most strains of HIV virus and that was vulnerable to an antibody attack (3). Based on structural constraints that stop the virus from mutating beyond certain points, researchers hypothesized that antibodies that targeted this spot would neutralize a wide variety of HIV strains.
Peter Kwong, chief of structural biology at VRC and an author on both of the recent papers, told BioTechniques that the site of vulnerability is similar to a door handle. In order to open a door, you need to have something to grab onto. "The door can really be elaborate and change all sorts of things, but you still have to open some handle," Kwong said. "There's a handle that exists on the virus that allows it to enter a cell, and that particular handle is a site of vulnerability." If a mutation occurred at the virus' site of vulnerability, the HIV virus would not be able to enter its hosts' cells for replication purposes. This structural constraint renders the site vulnerable because it cannot be changed to avoid antibodies.
"We hypothesized that antibodies could recognize this [site of vulnerability], but we didn't know what special properties would allow an antibody to do so," Peter Kwong, chief of structural biology at VRC, told BioTechniques. "We now know, not only do these antibodies exist, but we now know the one critical step that is required to make more of them."
The first paper describes how the antibodies—VRC01, VRC02 and VRC03—were identified as broadly neutralizing and that they binded to the site of vulnerability; the second peered deeper into the underlying chemistry of VRC01 using X-ray crystallography. Crystallography, said Kwong, as opposed to other technologies, is like physically being inside the Empire State Building, versus reading statistics about how large it is and how much concrete was used. Here they could see that VRC01 is about ten fold more affinity matured than the typical antibody, improving VRC01's ability to bind to the site of vulnerability.
Now, researchers are trying to figure out what triggers the immune system to extend the typical affinity maturation step during the creation of the effective VRC01 antibody. "We first hypothesized they exist, now we found them, and the third step is to teach immune systems to make more of them," said Kwong.
If they can figure out how to initiate this trigger in other people, then they will have the lesson plan for teaching other immune systems how to create their own broadly neutralizing antibodies. "We just have to solve that step," said Kwong. "Then we're there. We have a vaccine."
References
1. Zhou, T., I. Georgiev, X. Wu, Z. Yang, K. Dai, A. Finzi, Y.D. Kwon, J. Scheid, et al. 2010. Structural basis for broad and potent neutralization of HIV-1 by antibody VRC01. Science 329:811–7.
2. X. Wu, Z.Y. Yang, Y. Li, C. Hogerkorp, W.R. Schief, M.S. Seaman, T. Zhou, S.D. Schmidt, L. Wu, et al. 2010. Rational design of envelope identifies broadly neutralizing human monoclonal antibodies to HIV-1. Science 329:859–61.
3. Zhou, T., L. Xu, B. Dey, A.J. Hessell, D.V. Ryk, S. Xiang, X. Yang, M. Zhang, et al. 2007. Structural definition of a conserved neutralization epitope on HIV-1 gp120. Nature 445:732–737
"Ethics" is simply a last-gasp attempt by deist conservatives and
orthodox dogmatics to keep humanity in ignorance and obscurantism,
through the well tried fermentation of fear, the fear of science and
new technologies.
There is nothing glorious about what our ancestors call history,
it is simply a succession of mistakes, intolerances and violations.
On the contrary, let us embrace Science and the new technologies
unfettered, for it is these which will liberate mankind from the
myth of god, and free us from our age old fears, from disease,
death and the sweat of labour.
Rael
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