Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Late invasion of infected cells into the brain causes HIV dementia say Temple researchers

07.06.2004


Dementia in AIDS patients is caused by a large, late invasion of HIV-infected macrophages--large, long-lived cells of the immune system that travel throughout the body and ingest foreign antigens to protect against infection--into the brain, according to researchers at Temple University’s Center for Neurovirology and Cancer Biology (http://www.temple.edu/cnvcb/), debunking a longstanding "Trojan Horse" theory that early infection by macrophages remains latent until the latter stages of AIDS.


Jay Rappaport, professor of biology in the Center for Neurovirology and Cancer Biology at Temple University.




The results of their study, "Macrophage/Microglial Accumulation and Proliferating Cell Nuclear Antigen Expression in the Central Nervous System in Human Immunodeficiency Virus Encephalopathy," was published in the June issue of the American Journal of Pathology [June 2004; Volume 164, Number 6] (http://ajp.amjpathol.org/). The study was funded by the National Institute of Neurodegenerative Disorder and Stroke and the Howard Hughes Medical Institute.

"Basically, one of the longstanding models for how HIV causes dementia is the ’Trojan Horse’ model," says Jay Rappaport, Ph.D., a professor of biology at the Center, who led the study. "According to this model, early during HIV infection, there may be a few macrophages that are infected and get into the brain and establish an infection in the resident microglia [long-term resident macrophages of the brain]. Then, late in the disease, there’s a resurgence of the HIV virus from the macrophages." Rappaport and his collaborators believe that this longstanding theory does not hold true, that the early invasion of HIV-infected macrophages are controlled and cleared away by the body’s immune system.



"Late during AIDS, which is when most HIV patients develop dementia, there is a second--or late--invasion of infected macrophages which is not a ’Trojan Horse’ but a ’Trojan Herd,’" says Rappaport. "It’s not just a few cells, but a huge number invading the brain." Using markers, or antibodies, that can distinguish macrophages from resident microglia, the researchers were able to quantify the number of cells that appear to be macrophages and are producing the HIV virus.

"We found that there is about a 15- to 20-fold increase in the number of total macrophages in the brain during HIV dementia," Rappaport says. "Why are there so many cells? We believe that the perivascular cells [macrophages around the blood vessels], as they invade further into the brain, adapt to their location and take on the functional characteristics of the resident migroglia. "They’re then activated and there are many more of them," he adds.

Rappaport and his colleagues also looked at proliferation markers such as Ki67, but ruled out proliferation as being responsible for the increased number of infected cells.

"This study debunks the ’Trojan Horse’ model, it debunks the theory of a long latency in the brain by the infected cells," concludes Rappaport. "It suggests that trafficking of the macrophages late in infection is really responsible for dementia in HIV patients."

Rappaport has recently received a five-year, $2 million grant from the National Institutes of Health to continue exploring the trafficking of HIV-infected macrophages, not only in the brain, but in other organs of the body, and their role in the development of dementia in AIDS patients.

Preston M. Moretz | EurekAlert!
Further information:
http://www.temple.edu/cnvcb/
http://ajp.amjpathol.org

More articles from Life Sciences:

nachricht Navigational view of the brain thanks to powerful X-rays
18.10.2017 | Georgia Institute of Technology

nachricht Separating methane and CO2 will become more efficient
18.10.2017 | KU Leuven

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Osaka university researchers make the slipperiest surfaces adhesive

18.10.2017 | Materials Sciences

Space radiation won't stop NASA's human exploration

18.10.2017 | Physics and Astronomy

Los Alamos researchers and supercomputers help interpret the latest LIGO findings

18.10.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>