Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How HIV disables the cells’ call for help

08.07.2005


Weizmann Institute Scientists discover how an HIV protein fragment shuts down an immune response. Their finding may have implications for autoimmune disease treatment.



The HIV virus hides out in the very immune system cells that are meant to protect the body from viral infection. But how does it prevent these cells from mounting a full-scale attack against the invader? In research published today in the Journal of Clinical Investigation, a team at the Weizmann Institute of Science has shown how a part of a protein on the virus’ outer surface interferes with the cells’ normal immune response. But their work may have wider implications: this molecular fragment, which has such a devastating effect in one disease, might turn out to be an effective treatment for other disorders such as rheumatoid arthritis.

In the initial stages of HIV infection, the protein coatings of the viruses fuse with the outer membranes of T cells – immune system cells that recognize foreign invaders and alert other types of immune cell to come to the rescue. The genetic material of the virus, which is basically a strand of RNA, then forces the cell’s DNA to make copies of it. Newly minted viruses created by the host DNA later break out of the cell membrane to infect other cells. Many believed that the very act of breaking into T cells and hijacking their DNA was enough to destroy the ability of these cells to call up immune support.


But Institute scientists Prof. Yechiel Shai of the Biological Chemistry Department, Prof. Irun Cohen of the Immunology Department and graduate students Francisco Quintana and Doron Gerber thought there must be more to the story. T cells identify invaders using receptors, like security antennae, on their outer walls. A virus, especially one with its own surface equipment for seeking out specific T cells, would be hard-pressed to slip past these receptors without raising the alarm. The scientists surmised that the virus must be able to actively disable some part of the immune cell’s system.

They investigated a peptide fragment called FP (fusion peptide), a segment of the HIV protein gp41 found on the viral envelop. FP was known to play a role in the complex process in which the viral envelop fuses with the cell membrane in the initial stage of cell infection. The researchers suspected that FP, which is only exposed for a short period during this process, may have enough time to affect the immune response as well. Indeed, they found that FP locks on to several proteins on the cell walls that are involved in invoking a large-scale immune response, effectively shutting them down.

From their new understanding of how a tiny virus can gain control of the body’s immune response, the scientists made an intuitive leap. In autoimmune diseases, the same T cells that play host to HIV viruses are overactive, mistakenly attacking the body’s cells instead of foreign invaders. If the viruses use FPs to override the cells’ call for help, could their actions, which block one type of immune response without killing the cell, be applied to these autoimmune diseases? To check their theory, the research team tested FP on rats suffering from an autoimmune syndrome similar to human rheumatoid arthritis, and on cultured human T cells. As they predicted, the rats treated with FP showed a significant reduction in joint swelling and other symptoms of arthritis.

Shai points out that using FP, a tiny piece of a piece of the HIV virus, would pose no danger to patients as it lacks any ability to either infect cells or to reproduce. Rather, as the scientists note in their paper, the study of a destructive virus may contain important lessons on how to regulate the immune system. "Perhaps," says Cohen, "we humans can adopt the virus peptide to better control overactive autoimmunity."

Prof. Irun Cohen’s research is supported by the Minna James Heineman Stiftung; the Robert Koch Minerva Center for Research in Autoimmune Disease; and Mr. and Mrs. Samuel Theodore Cohen, Chicago, IL.

Prof. Cohen is the incumbent of the Helen and Morris Mauerberger Professorial Chair in Immunology.

Prof. Yechiel Shai’s research is supported by Robert Koch Minerva Center for Research in Autoimmune Disease; and the estate of Julius and Hanna Rosen.

Prof. Shai is the incumbent of the Harold S. and Harriet B. Brady Professorial Chair in Cancer Research.

Alex Smith | EurekAlert!
Further information:
http://www.weizmann-usa.org
http://www.jgordonassociates.com

More articles from Life Sciences:

nachricht Fingerprint' technique spots frog populations at risk from pollution
27.03.2017 | Lancaster University

nachricht Parallel computation provides deeper insight into brain function
27.03.2017 | Okinawa Institute of Science and Technology (OIST) Graduate University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Northern oceans pumped CO2 into the atmosphere

27.03.2017 | Earth Sciences

Fingerprint' technique spots frog populations at risk from pollution

27.03.2017 | Life Sciences

Big data approach to predict protein structure

27.03.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>