A new study shows, for the first time, that cow cells can naturally become immortal—continuing to divide indefinitely without genetic modification or any abnormal transformation. This overturns long-held assumptions that bovine cells could only be immortalized through gene editing, providing a safe, stable, and scalable source of cells for cultivated beef production. The finding removes one of the biggest technical and regulatory barriers to producing affordable cultivated beef, a potential game-changer for creating sustainable, ethical meat without the environmental toll of traditional livestock farming.
On a mission to reshape the future of sustainable food, researchers at the Hebrew University of Jerusalem and Believer Meats have unlocked a natural pathway to immortalize cow cells, marking a major step toward affordable, cultivated beef. The study, led by Prof. Yaakov Nahmias at the Grass Center for Bioengineering at Hebrew University and now published in Nature Food, reveals that bovine cells can spontaneously renew themselves indefinitely without genetic modification. While similar self-renewal was previously achieved in chicken cells, this study challenges the long-held assumption that such processes were not possible in large mammals due to their natural resistance to cellular transformation. This finding addresses one of the most stubborn bottlenecks in cultivated meat production, paving the way for safe, scalable production of cultivated beef and lamb.
“This work adds valuable new insights to the rapidly expanding knowledge base supporting cultivated meat development. Spontaneous immortalization attempts often fail because researchers simply abandon the process when cell growth slows. This study, demonstrating for the first time that bovine cells can be spontaneously immortalized, marks an exciting advance. By detailing the sequence of events that occur during cell line development, it provides a roadmap for non-GM approaches to be used for commercial cultivated meat production across the full range of animal species used in food production.”
— Dr. Elliot Swartz, Sr. Principal Scientist for Cultivated Meat, The Good Food Institute
Breaking Nature’s Code
In traditional cell biology, animal cells stop dividing after a certain number of generations and enter a state known as senescence. Until now, cattle cells could only be induced to bypass this limit by disabling genes involved in cell cycle regulation, raising regulatory and safety concerns.
“We showed chicken cells can immortalize without such interventions a few years ago, but the consensus in the field was that bovine cells could not do the same,” said Prof. Nahmias. “What worked relatively quickly in chickens became an exhaustive pursuit in bovine cells. We had to continuously culture bovine cells for more than 18 months before the first self-renewing colonies emerged.”
The researchers isolated cells from both Holstein and Simmental cows and grew them in the laboratory for over 500 days, tracking their progression through aging and senescence by day 180 of culture. Despite months of apparent inactivity, the team persisted—and after 240 cell generations, spontaneously renewing bovine cells emerged. Molecular analysis showed that the process did not involve any disruption of normal growth regulation and that the cells retained their DNA repair capabilities, indicating a natural, controlled pathway of renewal.
The researchers discovered that this process was driven by the natural activation of telomerase and PGC1α, allowing cells to reset their biological clocks by extending chromosomal ends and regenerating mitochondria.
Why It Matters
Beef is the most resource-intensive form of agriculture, responsible for deforestation, water depletion, and a significant share of global greenhouse gas emissions. Cultivated meat, grown from animal cells rather than livestock, has long been touted as a solution. However, challenges around cost and safety have slowed progress, especially for cultivated beef.
Stable, self-renewing cell lines are the foundation of any large-scale cell culture system, just as yeast or bacterial strains underpin pharmaceutical and food manufacturing. This study demonstrates a natural and safe route to establish these cell lines in cattle, suggesting that price parity with conventional beef could theoretically be reached using continuous cell-based manufacturing—bringing cultivated meat closer to mainstream viability.
Science, Patience, and Serendipity
According to Prof. Nahmias, “Months stretched into years, and perseverance replaced certainty. Then, after over 400 silent days, colonies suddenly appeared—a true eureka moment that overturned what we thought we knew about bovine cells.”
The discovery also sheds light on a long-standing biological puzzle known as Peto’s paradox—the observation that large animals rarely develop uncontrolled cell growth despite having far more cells. The team’s work suggests that the same natural defenses that protect large animals may make their cells more resistant to renewal until time and evolutionary forces allow adaptation.
Next Steps
The researchers are now investigating whether the same natural renewal process can occur in other mammals and whether these cells can be developed into muscle and fat tissues suitable for cultivated meat production.
Fluorescent microscopy of immortalized beef cells, mitochondria labeled green.
Credit: Nahmias Lab
The research paper, titled “Spontaneous immortalization of bovine fibroblasts following long-term expansion offers a non-transformed cell source for cultivated beef,” is now available in Nature Food at https://www.nature.com/articles/s43016-025-01255-3
DOI number 10.1038/s43016-025-01255-3.
Researchers:
Laura Pasitka1, Merav Cohen1,2, Shaun Regenbaum1, Avner Ehrlich1, Boaz Gildor3, Ariel Gold3, Yaakov Nahmias1,2,3
Institutions:
- Grass Center for Bioengineering, The Hebrew University of Jerusalem
- Silberman Institute of Life Sciences, The Hebrew University of Jerusalem
- Believer Meats; Rehovot
For a century, the Hebrew University of Jerusalem has been a beacon for visionary minds who challenge convention and shape the future. Founded by luminaries like Albert Einstein, who entrusted his intellectual legacy to the university, it is dedicated to advancing knowledge, cultivating leadership, and promoting diversity. Home to over 23,000 students from 90 countries, the Hebrew University drives much of Israel’s civilian scientific research and the commercialization of technologies through Yissum, its tech transfer company. Hebrew University’s groundbreaking contributions have been recognized with major international awards, including ten Nobel Prizes, two Turing Awards, and a Fields Medal. Ranked 88th globally by the Shanghai Ranking (2025), Hebrew University marks a century of excellence in research, education, and innovation. To learn more about the university’s academic programs, research, and achievements, visit the official website at http://new.huji.ac.il/en