Navigation Links
SIV infection may lead to increase in immune-suppressive Treg cells
Date:2/14/2012

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.


'/>"/>

Contact: Carole Gan
carole.gan@ucdmc.ucdavis.edu
916-734-9047
University of California - Davis Health System
Source:Eurekalert

Related medicine news :

1. Rothman at Jefferson research suggests abandon convention in diagnosing periprosthetic joint infection
2. Mouse Study Suggests Alzheimers Spreads Through Brain Like an Infection
3. Infections Might Raise Stroke Risk in Children: Study
4. Norovirus is the leading cause of infection outbreaks in US hospitals
5. Oral HPV Infection Strikes Men More Than Women: Study
6. Oral HPV infection, HPV-related cancers more common in men
7. IBD travelers are not at higher risk of contracting intestinal infections
8. Certain Seniors at Risk for Infection After ER Visit: Study
9. A new way to stimulate the immune system and fight infection
10. Anthrax capsule vaccine protects monkeys from lethal infection
11. Females may be more susceptible to infection during ovulation
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/23/2017)... ... April 23, 2017 , ... Altura Communication Solutions, a nationwide ... Select certification and SMB specialization. Altura is now qualified to sell, install ... the Select Certification, Altura fulfilled the training and exam requirements for the Cisco ...
(Date:4/22/2017)... ... April 22, 2017 , ... ... named PROSHRED® Security of Philadelphia its “Woman-Owned Small Business of the ... in providing information destruction , recycling, and compliance services to businesses ...
(Date:4/22/2017)... ... April 22, 2017 , ... ... role as Vice President of Sales and Business Development at OAKWORKS, Inc. ... partner engagements, business development, and strategic planning for the company. Recognized industry-wide ...
(Date:4/21/2017)... ... 21, 2017 , ... An April 10 article in the Daily ... reveal a great deal about prehistoric ice-age dental practitioners and their primitive and, no ... to remove decayed dental matter, and that teeth were then filled with bitumen, a ...
(Date:4/21/2017)... ... ... staff at Palm Beach Face is proud to announce that their practice founder, Michael ... take place on April 23rd, the London Marathon has a long tradition of raising funds ... team EMPOWER, raising money for the international charity, Smile Train. , Started in ...
Breaking Medicine News(10 mins):
(Date:4/20/2017)... April 20, 2017  Zimmer Biomet Holdings, Inc. (NYSE ... today announced that it will be participating in the ... the InterContinental Hotel in Boston, Massachusetts ... present at 11:20 a.m. Eastern Time. A ... Zimmer Biomet,s Investor Relations website at http://investor.zimmerbiomet.com .  ...
(Date:4/20/2017)... 2017  CVS Pharmacy, the retail division of ... store design to enhance the retail customer experience ... products and expanded beauty selections paired with informational ... new offerings. Together with its innovative digital programs, ... customer experience at CVS Pharmacy.  ...
(Date:4/20/2017)... PARIS , April 20, 2017 ... EyeCET platform, the first non-viral gene expression technology that ... in the eye to address a wide range of ... UK Medicines and Healthcare products Regulatory Agency (MHRA) to ... ...
Breaking Medicine Technology: