The extreme diversity of human immunodeficiency virus (HIV) strains is a major obstacle to anti-AIDS vaccine elaboration or the development of new treatments against the disease. IRD scientists, working jointly with other institutes (1), used statistical methods to determine the adaptive molecular mechanisms the virus deploys to avoid neutralization by the host immune defences. This adaptive molecular evolutionary strategy, based on genetic variability, proved to be a feature common to the different HIV subtypes. The virus apparently uses the great variety of its envelope-protein receptor binding sites, which have the role of fixing large complex carbohydrate molecules in the form of glycans, to provide protection against the host’s antibodies. These sugars are large structures that apparently block the way of human antibodies that would otherwise fix on to the virus, without hindering these envelope proteins in their function of attaching the virus to the host cell. These results open the way to potential ways of tackling AIDS.
In humans, the AIDS virus HIV manifests extreme genetic variability. It is particularly virulent, probably because its introduction into populations is recent (2). It has a potential for rapid evolution, at both population and individual scales, owing to a mutation rate among the highest in the living world, and to its recombination capacity. This high evolutionary potential is one of the major obstacles hindering the development of an effective vaccine. Starting from the principle that this mutation-based evolution of the virus is a response to selective pressures exerted by the host immune response (thought to be the dominant evolutionary force) , IRD researchers and their project partners (1) attempted to determine, at the molecular scale, the adaptive mechanisms at work and their comparative occurrence between the different HIV groups and subtypes. They used powerful statistical techniques (the codon-based maximum likelihood method) to investigate and compare the evolution of 3 major genes of the HIV genome, gag, pol and env. They did this for several HIV subtypes. They were able to confirm that the virus followed a dynamic adaptation strategy, based on the deployment of a shield of complex carbohydrates (glycans) to block antibody binding and thus provide protection against the host immune response.
Among the mutations randomly affecting the genome as a whole, those which influence the genes essential for viral survival and multiplication appear to be systematically selected against (negative selection). The gag gene, which codes for the proteins of the capsid (containing the genome and the viral proteins) and the pol gene, which allows synthesis of enzymes essential for virus replication, thus appear highly conserved and stable from one subtype to another.
Bénédicte Robert | EurekAlert!
Millions through license revenues
27.04.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn
New High-Performance Center Translational Medical Engineering
26.04.2017 | Fraunhofer ITEM
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences