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 Kidney tumor: Genetic trigger discovered
18.06.2018 | Julius-Maximilians-Universität Würzburg

nachricht New type of photosynthesis discovered
18.06.2018 | Imperial College London

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

Im Focus: Photoexcited graphene puzzle solved

A boost for graphene-based light detectors

Light detection and control lies at the heart of many modern device applications, such as smartphone cameras. Using graphene as a light-sensitive material for...

Im Focus: Water is not the same as water

Water molecules exist in two different forms with almost identical physical properties. For the first time, researchers have succeeded in separating the two forms to show that they can exhibit different chemical reactivities. These results were reported by researchers from the University of Basel and their colleagues in Hamburg in the scientific journal Nature Communications.

From a chemical perspective, water is a molecule in which a single oxygen atom is linked to two hydrogen atoms. It is less well known that water exists in two...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Novel method for investigating pore geometry in rocks

18.06.2018 | Earth Sciences

Diamond watch components

18.06.2018 | Process Engineering

New type of photosynthesis discovered

18.06.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>