Katalin Karikó, pictured, and Drew Weissman won the Nobel Prize for advances in mRNA research that led to the first Covid vaccines.
When Drew Weissman received a call from Katalin Karikó in the early morning hours this past Monday, he assumed his longtime research partner was calling to share a nascent, nagging idea. Weissman, a professor of medicine at the Perelman School of Medicine at the University of Pennsylvania, and Karikó, a professor at Szeged University and an adjunct professor at UPenn, both struggle with sleep disturbances. Thus, middle-of-the-night discourses between the two, often over email, has been a staple of their friendship. But this time, Karikó had something more pressing and exciting to share: They had won the 2023 Nobel Prize in Physiology or Medicine.
The work for which they garnered the illustrious award and its accompanying $1,000,000 cash windfall was completed about two decades ago, wrought through long hours in the lab over many arduous years. But humanity collectively benefited from its life-saving outcome three years ago, when both Moderna and Pfizer/BioNTech’s mRNA vaccines against COVID were found to be safe and highly effective at preventing severe disease. Billions of doses have since been given out to protect humans from the upstart viral scourge.
“I thought of going somewhere else, or doing something else,” said Katalin Karikó. “I also thought maybe I’m not good enough, not smart enough. I tried to imagine: Everything is here, and I just have to do better experiments.”
Unlocking the power of mRNA
Weissman and Karikó unlocked mRNA vaccines for the world back in the early 2000s when they made a key breakthrough. Messenger RNA molecules are essentially instructions for cells’ ribosomes to make specific proteins, so in the 1980s and 1990s, researchers started wondering if sneaking mRNA into the body could trigger cells to manufacture antibodies, enzymes, or growth agents for protecting against infection, treating disease, or repairing tissues. But there was a big problem: injecting this synthetic mRNA triggered a dangerous, inflammatory immune response resulting in the mRNA’s destruction.
While most other researchers chose not to tackle this perplexing problem to instead pursue more lucrative and publishable exploits, Karikó stuck with it. The choice sent her academic career into depressing doldrums. Nobody would fund her work, publications dried up, and after six years as an assistant professor at the University of Pennsylvania, Karikó got demoted. She was going backward.
“I thought of going somewhere else, or doing something else,” Karikó told Stat in 2020. “I also thought maybe I’m not good enough, not smart enough. I tried to imagine: Everything is here, and I just have to do better experiments.”
A tale of tenacity
Collaborating with Drew Weissman, a new professor at the University of Pennsylvania, in the late 1990s helped provide Karikó with the tenacity to continue. Weissman nurtured a goal of developing a vaccine against HIV-1, and saw mRNA as a potential way to do it.
“For the 20 years that we’ve worked together before anybody knew what RNA is, or cared, it was the two of us literally side by side at a bench working together,” Weissman said in an interview with Adam Smith of the Nobel Foundation.
In 2005, the duo made their 2023 Nobel Prize-winning breakthrough, detailing it in a relatively small journal, Immunity. (Their paper was rejected by larger journals, including Science and Nature.) They figured out that chemically modifying the nucleoside bases that make up mRNA allowed the molecule to slip past the body’s immune defenses. Karikó and Weissman followed up that finding by creating mRNA that’s more efficiently translated within cells, greatly boosting protein production. In 2020, scientists at Moderna and BioNTech (where Karikó worked from 2013 to 2022) rushed to craft vaccines against COVID, putting their methods to life-saving use.
The future of vaccines
Buoyed by the resounding success of mRNA vaccines, scientists are now hurriedly researching ways to use mRNA medicine against other infectious diseases, cancer, and genetic disorders. The now ubiquitous efforts stand in stark contrast to Karikó and Weissman’s previously unheralded struggles years ago as they doggedly worked to realize a shared dream that so many others shied away from. Katalin Karikó and Drew Weissman were brave enough to walk a scientific path that very well could have ended in a dead end, and for that, they absolutely deserve their 2023 Nobel Prize.
This article originally appeared on Big Think, home of the brightest minds and biggest ideas of all time.
In this illustration of immune defense, Y-shaped proteins called antibodies attack a virus.
When we get sick, our immune system sends its soldier cells to the battlefield. Called B-cells, they "examine" the foreign particles that shouldn't be in our bloodstream—and start producing the antibodies, the proteins to neutralize the invaders.
To screen the antibodies, scientists have developed a proprietary way to make the effective ones glow – like a literal "lightbulb" moment.
The better these antibodies are at neutralizing the pathogen, the faster we recover.
The antibodies acquired from COVID-19 survivors already showed promise in treating other patients, but because they must be obtained from people, generating a regular supply is not feasible. To close the gap, researchers are trying to identify the B-cells that make the best antibodies—and then farm them in laboratories at scale.
Scientists at Berkley Lights, a biotechnology company in California, have been screening B-cells from recovered patients and testing the antibodies they release for virus-neutralizing abilities. To screen the antibodies, scientists there have developed a proprietary way to make the effective ones glow – like a literal "lightbulb" moment.
So how does it work? First, the individual B-cells are placed into microscopic chambers called nano-pens, where they secrete the antibodies. Once released, the antibodies are flushed over tiny beads that have bits of the viral particles attached to them, along with special molecules that can emit fluorescent light.
"When an antibody binds to the bead, we see a bright light on the bead," explains John Proctor, the company's senior vice president of antibody therapeutics. "So we can identify which cells are making the antibodies."
Then the antibodies are tested for their ability to counteract the coronavirus's spike proteins, which the virus uses to break into our cells. Not all antibodies are equally good at this crucial defense move—some can block only parts of the virus's machinery, while others can neutralize it completely. Proctor and his colleagues are looking for the latter.
Once scientists identify the best performing B-cells, they crack the cells open—or in scientific terms "lyse" them—and extract the genetic instructions for making the antibodies. As it turns out, B-cells aren't very efficient at pumping out massive amounts of antibodies, so scientists insert these genetic instructions into a different, more prolific type of cell.
Named Chinese Hamster Ovary Cells or CHO, these cells are commonly used in the pharmaceutical industry because they can generate therapeutic proteins en masse. Under the right nutrient conditions, which include a lot of sugar, CHO cells can keep making the antibodies at commercial levels. "They are engineered to operate in very large bioreactors," Proctor explains.
While traditional antibody screening can take three months, the Beacon System can do it in less than 24 hours.
Berkeley Lights' technology has already been used to screen the antibodies of recovered patients from Vanderbilt University Medical Center. In another example, a biotech company GenScript ProBio used the platform to screen mice engineered to have human antibodies for the coronavirus.
In addition to its small, lab-on-a-chip size, Berkeley Lights' system allows scientists to greatly speed up the screening process. While traditional antibody screening can take three months, the Beacon System can do it in less than 24 hours. "We only need one B-cell per pen and a couple of beads to see that fluorescent signal," Proctor says. "It is a more advanced way to process and analyze cells, and that level of sensitivity is unique to our technology."
B-cells secreting antibodies inside the Berkeley Lights Beacon System Nano-Pens.
While vaccines are likely to take months to develop and test, antibodies might arrive to the battleground sooner. With the extremely limited treatment options for COVID-19, antibody-based therapeutics can potentially bridge this gap.
