Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists shed new light on how antibodies fight HIV

10.09.2007
New findings may further efforts to create AIDS vaccine

By furthering scientists’ understanding of the molecular mechanisms that separate the minority of successful HIV antibodies from the majority of ineffective antibodies, the work may have implications for future attempts to design an HIV vaccine.

The study was published on September 6, 2007, in the journal Nature.

“This study is part of the effort to understand how protection against HIV occurs,” says Dennis Burton, a professor at The Scripps Research Institute. “If we really understand this, then we can design tailor-made vaccines in a way that has never been done before.”

... more about:
»B12 »CASCADE »HIV »LALA »Pathogen »Vaccine »immune cell »infected »receptor

Although vaccines have long been used with great success to prevent diseases, scientists are still learning about the exact mechanisms of how vaccines work and how the antibodies that vaccines prompt the body to create can neutralize a pathogen. The spread of HIV, which is resistant to most antibodies the body produces against it, has made fully understanding this method of action more urgent.

With this in mind, Burton and colleagues sought to tease apart the action of the b12 antibody-one of the rare antibodies that protects against the HIV virus. The antibody, first identified by Burton, Scripps Research Professor Carlos Barbas III, and colleagues in 1992, originally came from the bone marrow of a 31-year-old male who had been HIV positive without symptoms for six years.

In the current study, researchers created mutated versions of b12 to see what effect various changes would have on the antibody’s effectiveness.

“Hopefully, we can work backwards towards a vaccine, using b12 and the very few other really great, broadly neutralizing antibodies against HIV that have been found,” says Scripps Research Senior Research Associate Ann Hessell, who was first author of the Nature paper jointly with Lars Hangartner, a Scripps Research postdoctoral fellow.

Results from the new study suggest the importance of antibody activity against both infected cells and free virus for effective protection. As well as simply binding to HIV, protection was dependent upon the ability of antibodies to interact with immune cell Fc receptors.

Fc receptors are found on the surface of immune cells, such as natural killer cells. The Fc receptor binds to the Fc region of an antibody after an antibody binds to a pathogen, targeting the pathogen for attack by the immune system. Although Fc receptor function was known to be important for the function of antibodies against other diseases, a role in protecting against HIV had never before been demonstrated.

Burton’s team examined the ability of two antibodies mutated from b12, dubbed KA and LALA, to prevent infection using the SHIV/macaque model, in which macaques are challenged with a hybrid human-simian virus that infects the model but is recognized by human antibodies. The KA antibody contained a mutation that prevented it from interacting with the complement cascade, a major component of the immune system responsible for destroying invading pathogens. The LALA antibody contained a mutation that rendered it unable to interact with either the complement pathway or the Fc receptor.

In both mutants, the site where the antibody binds to free-floating virus was unaltered, allowing the researchers specifically to investigate the importance of the complement cascade and Fc receptor system for preventing infection.

“We saw that the KA antibody, which could still bind to the Fc receptors on the immune cells but not to the complement cascade, protected the animals from becoming infected just as the wild type b12 antibody,” says Hessell. “In contrast, the LALA group became infected much like the controls.”

The results provide the first evidence that the Fc receptor, but not the complement cascade, is important to the function of the b12 antibody in preventing HIV infection.

Additional in vitro experiments revealed that the wild type and KA antibodies, but not the LALA antibody, blocked infection more efficiently in the presence of other effector cells of the immune system.

“Our results are fully consistent with the antibody doing two jobs,” says Burton, “job one, stick to the virus; job two, recruit immune cells to come and kill infected cells.”

Keith McKeown | EurekAlert!
Further information:
http://www.scripps.edu

Further reports about: B12 CASCADE HIV LALA Pathogen Vaccine immune cell infected receptor

More articles from Life Sciences:

nachricht Cnidarians remotely control bacteria
21.09.2017 | Christian-Albrechts-Universität zu Kiel

nachricht Immune cells may heal bleeding brain after strokes
21.09.2017 | NIH/National Institute of Neurological Disorders and Stroke

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

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...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

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

Comet or asteroid? Hubble discovers that a unique object is a binary

21.09.2017 | Physics and Astronomy

Cnidarians remotely control bacteria

21.09.2017 | Life Sciences

Monitoring the heart's mitochondria to predict cardiac arrest?

21.09.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>