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 Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton 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: 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 >>>