Researchers develop new technique to tap full potential of antibody libraries

January 15, 2009

In hopes of more fully tapping the libraries' potential, a group of Scripps Research Institute scientists, led by Scripps Research President Richard A. Lerner, M.D., has for the first time developed a new screening technique that enables antibody screening against equally massive libraries of targets. This technique makes it possible to accelerate searches for new treatments against cancer and other diseases.

The work is being reported in this week's Early Edition of the journal Proceedings of the National Academies of Science (PNAS).

The immune system produces antibodies to immobilize invaders, such as bacteria and viruses, by attaching to proteins referred to as antigens on those invaders. For many years, researchers have been producing huge collections of synthetic antibodies that collectively dwarf the number of antibodies humans produce naturally. These resources are a synthetic immune system with almost limitless potential, but existing techniques have only enabled screening the millions upon millions of available antibodies against handfuls of antigens.

"Many scientists have long recognized that efficient and sufficient access to the libraries demands an effective technique for also screening target antigens by the millions," said Lerner. "This work now makes that possible."

Traditional antibody research has involved developing systems in which the antibodies to be tested are incorporated into yeast cells, bacterial viruses known as phages, or some other form of "display" for testing against a target antigen protein. Past attempts to instead screen antibody libraries against antigen libraries have been stymied by a variety of technical challenges.

A key aspect to the success of the Lerner group's technique is using yeast cells to display the antibodies for screening, while using phages for the antigens, with each display labeled by a different colored fluorescent protein.

Screen results are determined using flow cytometry, a technique that allows the researchers to examine images of the yeast cells and phage particles and manipulate them. Using the differing displays means that antibody-antigen pairs that bind can be easily identified, because they show both fluorescent dye tag colors. Bound pairs are then filtered out of the mix for identification of the antibody and antigen involved, which requires genetic sequencing.

"It took us a while to get to the right conditions," says Diana Bowley, Ph.D., a Scripps Research staff scientist and the paper's first author with Teresa Jones, a Scripps Research scientific associate, "but now that we have, it's quite easy to visualize and isolate the antibody-antigen pairs."

To prove the concept, the group focused its initial experiments on a known interaction between a specific antibody and a fragment of a protein found on the outside of HIV particles. The group worked with some 10 million antibodies, but the library was weighted to include a known antibody. The antigen library was of similar size and comparably weighted to include the known HIV antigen. The weighting guaranteed the existence of an antibody-antigen pair, which in turn allowed the group to tweak its initial concept until it could identify pairings at the expected rate.

The group was able to successfully identify the expected pairings, proving the new technique's potential to enable screening of large antibody and antigen libraries. "We're still deciding where to take it next," says Bowley. One likely direction would be to work with a broad group of cancer proteins, which should identify antibodies with potential as new cancer treatments.

Source: Scripps Research Institute

Explore further: Common yeast may worsen IBD symptoms in Crohn's disease

Related Stories

Common yeast may worsen IBD symptoms in Crohn's disease

March 8, 2017

During the past decade, the gut has experienced a renaissance as investigations focus on the role of the microbiome on human health. While most studies have focused on bacteria, the dominant microbial inhabitants in the gut, ...

Antibody treatment efficacious in psoriasis

September 30, 2015

An experimental, biologic treatment, brodalumab, achieved 100 percent reduction in psoriasis symptoms in twice as many patients as a second, commonly used treatment, according to the results of a multicenter clinical trial ...

The microbial superhero in your vagina

October 11, 2016

The aisle is marked with a little red sign that says "Feminine Treatments". Squeezed between the urinary incontinence pads and treatments for yeast infections, there is a wall of bottles and packages in every pastel shade ...

Recommended for you

Where body fat is carried can predict cancer risk

May 23, 2017

Scientists have found that carrying fat around your middle could be as good an indicator of cancer risk as body mass index (BMI), according to research published in the British Journal of Cancer today.

Study offers guidance for targeting residual ovarian tumors

May 23, 2017

Most women diagnosed with ovarian cancer undergo surgery to remove as many of the tumors as possible. However, it is usually impossible to eliminate all of the cancer cells because they have spread throughout the abdomen. ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.