Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scripps Research Scientists Devise Powerful New Method for Finding Therapeutic Antibodies

12.09.2012
The Technique Hones and Expands the Power of Large Numbers

Scientists at The Scripps Research Institute have found a new technique that should greatly speed the discovery of medically and scientifically useful antibodies, immune system proteins that detect and destroy invaders such as bacteria and viruses.

New methods to discover antibodies are important because antibodies make up the fastest growing sector of human therapeutics; it is estimated that by 2014 the top-three selling drugs worldwide will be antibodies.

The new technique, described in an article this week published online ahead of print by the journal Proceedings of the National Academy of Sciences, enables researchers to search large libraries of antibodies and quickly select the ones with a desired biological effect. It also provides for the creation of unusual, asymmetric antibodies whose capabilities extend beyond those of natural antibodies. The Scripps Research scientists demonstrated the power of the technique by using it to find an asymmetric antibody that almost perfectly mimics the activity of erythropoietin (EPO), a medically valuable hormone.

“Traditionally we’ve looked at antibodies as tools for binding to specific targets, but we should view them more generally, as tools for probing and altering functions in cells,” said Richard Lerner, the Lita Annenberg Hazen Professor of Immunochemistry and member of the Department of Molecular Biology at Scripps Research who led the new study.

At the Vanguard
Lab-grown antibodies already represent a major part of the ongoing biotechnology revolution. Used as scientific probes or medical therapies, they recreate the versatility of natural antibodies, which are produced by immune cells in a vast diversity to bind to highly specific shapes on viruses, bacteria, and other targets.
Two decades ago, Lerner and his laboratory at Scripps Research, in parallel with the group of Sir Gregory Winter at the Laboratory of Molecular Biology in Britain, developed the first techniques for generating very large libraries of combinatorial antibodies and quickly isolating those that can bind to a desired target. Since then, such techniques have been used to find antibodies to treat cancer, arthritis, transplant rejection, and other conditions. Humira, an anti-inflammatory antibody that was discovered this way, is expected to be the world’s top-selling drug this year. Belimumab (Benlysta®) was approved by the US Food and Drug Administration in 2011 to treat lupus, becoming the first new drug to treat the chronic, life-threatening inflammatory disease in more than 50 years.

Current antibody-discovery techniques have one big drawback, however. Although they can rapidly find antibodies that bind tightly to a known target, they can’t rapidly determine which of those antibodies has useful biological activity. An antibody may bind tightly to a virus without affecting the virus’s ability to infect cells, for example, or it may bind to a cellular receptor without activating that receptor. With current techniques, determining the overall biological effect of a target-binding antibody typically requires further, painstaking analysis.

A More Direct Path

In the new study, Lerner and his postdoctoral researcher Hongkai Zhang sought a method for rapidly finding antibodies that have a desired effect on cells, not just a desired ability to bind to a target. As a proof of principle, they aimed to discover an antibody that could mimic the activity of EPO, a hormone that stimulates red blood cell production. Drugs that mimic EPO’s effect are commonly used to treat anemia and related conditions.

Zhang began by using traditional techniques to quickly sift through a large antibody library to find tens of thousands of antibodies that bind tightly to the EPO receptor. He then stepped beyond traditional techniques, by taking the genes that encoded these EPO-receptor-binding antibodies and inserting them into lentiviruses. Unlike the phage viruses used in traditional methods, lentiviruses can usefully infect mammalian cells, delivering their payloads – antibodies, in this case – into a more human-like cellular environment.

Zhang applied this new library of antibody-coding lentiviruses to a single, large culture of mammalian test cells. The cells were of a type that express EPO receptors and proliferate when these receptors are bound by EPO proteins – or by antibodies that effectively mimic EPO. Each of these cells could host only a few viral particles at most, so in this way Zhang was able to distribute the entire library of EPO-receptor-binding antibodies broadly within the cell culture. Zhang also cultured the cells in a special way that prevented antibodies secreted by one cell from spreading easily to nearby cells and muddying any cause-effect relationship. “This concern over the diffusion of antibodies in the culture was one of the factors that had discouraged other researchers from using such a technique,” said Zhang.

After the lentiviruses had delivered the antibodies to the cultured cells, Zhang was able to note which cells were proliferating the most – signifying the presence of antibodies that mimic EPO. To identify the antibodies responsible, Zhang had only to harvest these faster-growing cells and sequence the antibody genes inside them.

This method quickly yielded an antibody that in a further test showed about 60 percent of the biological activity of natural EPO – which was as good as any antibody EPO-mimic that had ever been described.
Opening the Door to the Unknown

But Zhang and Lerner also noted that many of the proliferating cells had been infected by multiple lentivirus particles, and contained sequences from more than one antibody. Puzzlingly, Zhang found that when he recreated antibodies from these sequences, and tested them individually or in combinations, they showed no significant EPO-mimicking effect. Further tests showed that the source of the EPO-mimicking effect in the test cells was an antibody that does not occur naturally.

An antibody of the type used in the study has a Y-shaped structure, normally with two identical binding arms. But the presence of multiple antibody genes within some of Zhang’s test cells meant that, in a few cases, antibodies assembled themselves with two different binding arms. One of these “bispecific” antibodies turned out to bind to the EPO receptor – which has two binding sites – in a way that very accurately mimics the binding of a natural EPO molecule. “It turned out to be 100 percent as potent as authentic EPO in further tests,” Zhang said.

The serendipitous finding represents another major innovation, for, in principle, it extends the medical and scientific antibody repertoire from the 100 billion or so known variants of same-armed antibodies to an astronomically higher number of bispecific variants. Experiments to test such variants will be limited by the maximum number of usable cells in cultures, but that number is still very high, on the order of 10 million. “That allows for a lot of unique binding events,” said Lerner. “You probably can get almost anything that way.”

Lerner emphasizes that this new antibody-engineering/discovery technique can be used not just against known targets such as the EPO receptor, but also against cellular functions involving targets that have not yet been found. “The real power of this technique is its ability to help us discover the unknown,” he said.

Another author of the study, titled “Selection of antibodies that regulate phenotype from intracellular combinatorial antibody libraries,” was Ian A. Wilson, the Hansen Professor of Structural Biology at Scripps Research and an expert on the structure of the EPO receptor. For more information on the paper, see http://www.pnas.org/content/early/2012/09/05/1214275109.abstract

About The Scripps Research Institute

The Scripps Research Institute is one of the world's largest independent, not-for-profit organizations focusing on research in the biomedical sciences. Over the past decades, Scripps Research has developed a lengthy track record of major contributions to science and health, including laying the foundation for new treatments for cancer, rheumatoid arthritis, hemophilia, and other diseases. The institute employs about 3,000 people on its campuses in La Jolla, CA, and Jupiter, FL, where its renowned scientists—including three Nobel laureates—work toward their next discoveries. The institute's graduate program, which awards Ph.D. degrees in biology and chemistry, ranks among the top ten of its kind in the nation. For more information, see www.scripps.edu.
For information:
Office of Communications
Tel: 858-784-8134
Fax: 858-784-8136
press@scripps.edu

Mika Ono | EurekAlert!
Further information:
http://www.scripps.edu

More articles from Health and Medicine:

nachricht The cytoskeleton of neurons has been found to be involved in Alzheimer's disease
18.01.2019 | University of the Basque Country

nachricht Bioinspired nanoscale drug delivery method developed by WSU, PNNL researchers
10.01.2019 | Washington State 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: Ten-year anniversary of the Neumayer Station III

The scientific and political community alike stress the importance of German Antarctic research

Joint Press Release from the BMBF and AWI

The Antarctic is a frigid continent south of the Antarctic Circle, where researchers are the only inhabitants. Despite the hostile conditions, here the Alfred...

Im Focus: Ultra ultrasound to transform new tech

World first experiments on sensor that may revolutionise everything from medical devices to unmanned vehicles

The new sensor - capable of detecting vibrations of living cells - may revolutionise everything from medical devices to unmanned vehicles.

Im Focus: Flying Optical Cats for Quantum Communication

Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.

In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...

Im Focus: Nanocellulose for novel implants: Ears from the 3D-printer

Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing.

It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains:

Im Focus: Elucidating the Atomic Mechanism of Superlubricity

The phenomenon of so-called superlubricity is known, but so far the explanation at the atomic level has been missing: for example, how does extremely low friction occur in bearings? Researchers from the Fraunhofer Institutes IWM and IWS jointly deciphered a universal mechanism of superlubricity for certain diamond-like carbon layers in combination with organic lubricants. Based on this knowledge, it is now possible to formulate design rules for supra lubricating layer-lubricant combinations. The results are presented in an article in Nature Communications, volume 10.

One of the most important prerequisites for sustainable and environmentally friendly mobility is minimizing friction. Research and industry have been dedicated...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Our digital society in 2040

16.01.2019 | Event News

11th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Aachen, 3-4 April 2019

14.01.2019 | Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

 
Latest News

Additive manufacturing reflects fundamental metallurgical principles to create materials

18.01.2019 | Materials Sciences

How molecules teeter in a laser field

18.01.2019 | Life Sciences

The cytoskeleton of neurons has been found to be involved in Alzheimer's disease

18.01.2019 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>