Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UIC researchers discover how HIV rapidly infects immune cells

02.05.2003


Solving a longstanding scientific puzzle, researchers at the University of Illinois at Chicago have not only discovered how the body’s first line of defense against dangerous microbes inadvertently helps HIV rapidly infect the human immune system.



They’ve filmed the process as well.

In a remarkable series of movies created with images from time-lapse microscopy, UIC microbiologists Thomas Hope and David McDonald have documented how HIV enters human T cells, where it multiplies with abandon and eventually subverts the entire immune system, causing AIDS.


The movies show how HIV co-opts the very mechanism the body has evolved to defend itself against such pathogens.

"A picture is worth a thousand words," Hope said, quoting a colleague at a recent scientific meeting. "A video is worth a million."

The paper detailing the findings was accepted for publication in Science less than two weeks ago and was rushed to print in the May 1 online version of the journal called Science Express, which highlights scientifically important and newsworthy studies.

In the early stages of any infection, the dendritic cells of the immune system -- the first responders -- spring into action. These are the "garbage men of the body," as Hope calls them, constantly patrolling the neighborhood, looking for garbage to clean up.

Normally, when the dendritic cells find a piece of garbage -- a virus or other pathogen -- they pick it up and degrade it into tiny bits. They then show those bits to the T cells, alerting these executives of the garbage company to the potential danger.

The dendritic cells do this by making physical contact with the T cells, forming a tight interface, called an immunological synapse, through which the cells talk to one another via molecular signals.

If they make the right connection, the T cells then mobilize the rest of the immune system, sending out the trucks -- other immune cells -- to hunt for the garbage that the dendritic cells spotted, destroy the material, and save the body from disease.

While dendritic cells pick up HIV, however, they don’t destroy all the virus. Instead, scientists recently discovered, they inadvertently encourage infection, somehow helping HIV more rapidly infect the T cells.

McDonald said the "somehow" has now been answered.

Using a fluorescent dye that makes HIV particles glow green, Hope and McDonald photographed living dendritic cells with HIV particles inside. When the cells made contact with other cells, the HIV particles began streaming toward the juncture.

Not only that, but certain surface proteins on T cells necessary for infection by HIV also moved to the point of contact.

Further images clearly showed HIV particles transferring from the dendritic cells into the T cells through that same site -- the "infectious synapse," as the researchers call it.

Just as the immunological synapse signals the start of the immune response, so the infectious synapse jump-starts infection.

"HIV exploits the dendritic machinery for its own ends, taking advantage of the cells’ special relationship with T cells to gain entry and launch its assault," McDonald said. "Moreover, HIV doesn’t get destroyed in the process."

"What viruses do is try to find weak points in the immune system and take advantage of them," Hope said. "It’s a billion-year-old war: the body builds defenses against viruses, and the viruses find ways to thwart those defenses."

The researchers are particularly excited about their finding because it may apply to other pathogens. Recent studies have shown that Ebola virus, cytomegalovirus and the bacterium that causes tuberculosis all hitch rides on the dendritic cells just as HIV does.

"These pathogens appear to have discovered the same weak point in the immune system and exploited it," Hope said. "If true, then we may have discovered an important target for therapies that would combat not just HIV but many infectious diseases."

Sharon Butler | EurekAlert!
Further information:
http://www.uic.edu/

More articles from Health and Medicine:

nachricht Usher syndrome: Gene therapy restores hearing and balance
25.09.2017 | Institut Pasteur

nachricht MRI contrast agent locates and distinguishes aggressive from slow-growing breast cancer
25.09.2017 | Case Western Reserve University

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: The fastest light-driven current source

Controlling electronic current is essential to modern electronics, as data and signals are transferred by streams of electrons which are controlled at high speed. Demands on transmission speeds are also increasing as technology develops. Scientists from the Chair of Laser Physics and the Chair of Applied Physics at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have succeeded in switching on a current with a desired direction in graphene using a single laser pulse within a femtosecond ¬¬ – a femtosecond corresponds to the millionth part of a billionth of a second. This is more than a thousand times faster compared to the most efficient transistors today.

Graphene is up to the job

Im Focus: LaserTAB: More efficient and precise contacts thanks to human-robot collaboration

At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.

Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Goodbye, login. Hello, heart scan

26.09.2017 | Information Technology

The material that obscures supermassive black holes

26.09.2017 | Physics and Astronomy

Ageless ears? Elderly barn owls do not become hard of hearing

26.09.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>