Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

SIV infection may lead to increase in immune-suppressive Treg cells

15.02.2012
Original research and accompanying editorial highlight mechanism for regulatory T-cell accumulation in lymphoid tissue
Tissue in monkeys infected with a close relative of HIV can ramp up production of a type of T cell that actually weakens the body's attack against the invading virus. The discovery, in lymph nodes draining the intestinal tract, could help explain how the HIV virus evades the body's immune defenses.

If the same pattern is found in people infected with HIV, the finding could lead to a treatment strategy that slows the production of this restraining type of T cell. This would let the immune soldiers go after the virus more aggressively.

The scientists don't know if the simian virus is directly causing the build-up of the inhibitory T cells, called regulatory T cells, but in any case, reducing regulatory T-cell production could boost the body's resistance to the evasive virus.

The research was a collaboration among scientists at the UC Davis School of Medicine, Cincinnati Children's Hospital and the California National Primate Center.

Regulatory T cells, or Tregs, normally tamp down immune-system attacks, presumably to prevent an over-active assault that can cause harmful inflammation or auto-immune disease. The scientists suspect that the high number of Treg cells in the infected primates might prevent their immune systems from mounting a full-on attack against the virus.

The researchers focused on immune cells called dendritic cells that interact with Tregs in preparation for their policing duty. This occurs in lymph nodes throughout the body's lymphatic system -- the part of the circulatory system that also drains many organs of fluids, fatty acids and other substances.

The study found that mature dendritic cells were particularly active in promoting Treg production, and that these promoters were in high concentration in nodes draining the intestine, or mucosa. The intestinal mucosa is the site of early infection and aggressive transmission for both the primate virus and HIV, making it the first line of defense against the invasion.

"The intestinal mucosa contains highly activated 'helper' T-cells that are prime targets for the HIV virus, so it is important to understand how the body fights HIV in this under-studied tissue," said Barbara Shacklett, associate professor of medical microbiology and immunology at the UC Davis School of Medicine.

"We consider the GI tract as a major 'battlefield' between the immune system and HIV. If we can better understand what happens there, we may finally learn how to eradicate the virus," said Shacklett.

Shacklett is a co-author of a paper on the research, entitled "Myeloid dendritic cells isolated from tissues of SIV-infected Rhesus macaques promote the induction of regulatory T cells," published Jan. 28 in the journal AIDS. Julia Shaw, a graduate student in Shacklett's lab, co-led the research with Pietro Presicce of the Cincinnati Children's Hospital Research Foundation.

An editorial in the same issue of AIDS highlights the new research and related studies that are clarifying the interaction between the simian version of HIV and the Treg cells that can control attacks against them.

Shacklett stressed that Tregs usually increase when the immune system is at risk of over-reacting. Their high numbers lead to a reduced immune attack, although the mechanism is not well understood.

But in persistent infections -- when a strong immune response is called for -- Tregs should decrease in number, taking a "hands-off" approach and freeing the immune army to advance. HIV may sabotage this control by prompting increased Treg production as if the body need not rally its defenses against the virus.

The research draws on earlier research by Shacklett, Shaw and colleagues comparing Treg counts in rectal mucosa of people with high and low HIV viral load. They showed that high viral load was associated with increased frequencies of immunosuppressive Treg in the gastrointestinal mucosa, suggesting these Tregs might be thwarting the body's immune defenses.

Other coauthors on the new research paper are Claire Chougnet, an associate professor of molecular immunology at University of Cincinnati College of Medicine, and Christopher Miller of the California National Primate Research Center.

The research was supported in part by the California National Primate Research Center's Pilot Project award funded by BaseGrant NCRR-RR-000169 and the National Institutes of Health grants AI8227, AI068524 and AI057020.

The UC Davis School of Medicine is among the nation's leading medical schools, recognized for its research and primary-care programs. The school offers fully accredited master's degree programs in public health and in informatics, and its combined M.D.-Ph.D. program is training the next generation of physician-scientists to conduct high-impact research and translate discoveries into better clinical care. Along with being a recognized leader in medical research, the school is committed to serving underserved communities and advancing rural health. For more information, visit UC Davis School of Medicine at medschool.ucdavis.edu

Carole Gan | EurekAlert!
Further information:
http://www.ucdmc.ucdavis.edu

Further reports about: Aids HIV HIV virus Medicine SIV T cells T-cell dendritic cells fatty acid immune cell immune defense immune system lymph node primate

More articles from Health and Medicine:

nachricht Penn vet research identifies new target for taming Ebola
12.01.2017 | University of Pennsylvania

nachricht The strange double life of Dab2
10.01.2017 | University of Miami Miller School of Medicine

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>