Katalin Karikó: The Persistence and Development of mRNA Technology

In 1985, Katalin Karikó emigrated from Hungary to the United States after her research laboratory at the Biological Research Centre in Szeged lost its funding. Relocating with her family, she brought the equivalent of £900, which they had acquired on the black market and hidden inside her daughter's teddy bear.

Karikó, a biochemist, was focused on the therapeutic potential of messenger RNA (mRNA). Despite widespread skepticism in the scientific community regarding the viability of mRNA applications, she theorized that delivering synthesized mRNA could instruct cells to produce specific proteins, offering a novel approach to medical treatments. Her research laid the foundational science for the mRNA COVID-19 vaccines developed by Pfizer-BioNTech and Moderna, earning her the 2023 Nobel Prize in Physiology or Medicine.

Early Life and Move to the US

Born in 1955 in rural Hungary, Karikó developed an early interest in biology, influenced by her father's work as a butcher. She excelled academically, becoming a national biology champion in her youth.

After securing a position at Temple University in Philadelphia, she left Hungary in 1985 due to the lack of funding for her research.

Research Challenges and the Inflammatory Response

Throughout the 1990s, mRNA research was widely considered a therapeutic dead end. The primary obstacle was the severe inflammatory response triggered when synthetic mRNA was introduced into laboratory animals. The immune system recognized the synthetic mRNA as a foreign pathogen, activating Toll-like receptors and initiating a systemic inflammatory reaction.

Karikó, working as a research assistant professor at the University of Pennsylvania, struggled to secure grant funding for her mRNA research. In 1995, facing institutional pressure to shift her focus, she accepted a demotion rather than abandon her work on mRNA.

In 1997, she began collaborating with Drew Weissman, an immunologist at the University of Pennsylvania who was researching HIV vaccines. Together, they focused on identifying why synthetic mRNA caused an immune response while naturally occurring mRNA did not.

The Pseudouridine Discovery

In 2005, Karikó and Weissman published a pivotal discovery. They identified that natural human mRNA contains chemical modifications that prevent it from triggering the immune system. Synthetic mRNA lacked these modifications.

They found that by replacing the nucleoside uridine in the synthetic mRNA with pseudouridine, a naturally occurring modification, the mRNA no longer provoked an inflammatory immune response. Furthermore, this modification significantly increased the efficiency of protein translation. This discovery provided a mechanism to safely administer synthetic mRNA to produce desired proteins without severe side effects.

Despite its eventual significance, their research published in Immunity initially received limited attention from the broader scientific community.

Transition to BioNTech and Vaccine Development

In 2013, following continued difficulties securing a tenured position at the University of Pennsylvania, Karikó joined BioNTech, a German biotechnology company founded by Ugur Sahin and Özlem Türeci. BioNTech was exploring the use of mRNA technology for cancer immunotherapy.

When the genetic sequence for SARS-CoV-2 was published in early 2020, BioNTech, in partnership with Pfizer, utilized Karikó and Weissman's modified mRNA technology to rapidly develop a COVID-19 vaccine. The pseudouridine modification was critical to the vaccine's safety and efficacy.

Continued Impact

Katalin Karikó continues to advocate for the broad therapeutic potential of mRNA technology, which is currently being researched for applications in various diseases, including cancer and genetic disorders. Her persistence in advancing mRNA research, despite decades of institutional and financial setbacks, proved critical to the rapid development of mRNA vaccines.