Leonard Hayflick

Leonard Hayflick (1928- ) is a scientist best known for the idea of the Hayflick limit, which states that human cell cultures in vitro will only divide 46-50 times. This idea is part of the foundation of the idea of a Maximum lifespan limit in humans.

# Leonard Hayflick (1928- )

by Zane Bartlett
 Keywords: Hayflick Limit

During the twentieth and twenty-first centuries in the United States, Leonard Hayflick
 studied the processes by which cells age. In 1961 at the Wistar
Institute in the US, Hayflick researched a phenomenon later called the
Hayflick Limit, or the claim that normal human cells can only divide
forty to sixty times before they cannot divide any further. Researchers
later found that the cause of the Hayflick Limit is the shortening of
telomeres, or portions of DNA at the ends of chromosomes that slowly
degrade as cells replicate. Hayflick used his research on normal
embryonic cells to develop a vaccine for polio, and from Hayflick’s
published directions, scientists developed vaccines for rubella, rabies,
 adenovirus, measles, chickenpox and shingles.

 Hayflick was born
 on 20 May 1928 in Philadelphia, Pennsylvania, to Edna Hayflick and
Nathan Hayflick. His father designed prosthetics for dental patients.
When Hayflick was nine, one of his uncles bought him a chemistry set.
Hayflick’s parents allowed him to build a laboratory in the basement of
their home, where he performed biology and chemistry experiments.
Hayflick attended John Bartram High School in Philadelphia. During some
of his first chemistry lectures, Hayflick corrected his teacher, who
then allowed him to help in the chemical stockroom, where Hayflick
acquired more chemicals for his studies.

 Hayflick enrolled in the University of Pennsylvania
 in Philadelphia in January 1946 but postponed his studies for military
service. After he served in the military for eighteen months from 1946
to 1948, Hayflick received a four-year scholarship through the GI Bill, a
 US federal government initiative to help veterans return to civilian
life after World War II. Hayflick studied microbiology at the University of Pennsylvania
 and graduated in 1951. After graduating, Hayflick took a job as a
research assistant in bacteriology in 1951 with Merck, Sharp, and Dohme
laboratories in North Wales, Pennsylvania. According to Hayflick, he
felt that graduate school would have been too difficult for him until he
 met a friend who studied bacteria species in the genus *Mycoplasma*, which are bacteria often involved in pneumonia and other diseases. Those studies convinced him to return to the University of Pennsylvania to receive a Master’s degree for his study of *Mycoplasma*. While at the University of Pennsylvania, Hayflick also met Ruth Heckler, whom he married and with whom he had five children.

 As a Master’s student, Hayflick’s mentor Warren Stinebring sent him to the Wistar Institute to research an infection in a rat colony. Hayflick showed that the infection was due to *Mycoplasmas*.
 Hayflick received a Master’s degree in medical microbiology in 1953. He
 won a fellowship to a PhD program, in which he continued his research.
Hayflick received a PhD in medical microbiology and chemistry in 1956
from the University of Pennsylvania.

 In
 1956, Hayflick moved to the department of microbiology at the
University of Texas in Galveston, Texas. He worked with cell culturist
Charles Pomerat. With Pomerat, Hayflick learned techniques to produce
cell cultures, or populations of cells living in controlled conditions.
When the fellowship at the University of Texas expired, Hayflick applied
 for work elsewhere. In 1958, the new director of the Wistar Institute,
Hilary Koprowski, offered Hayflick a job to culture cells for the other
scientists at the institute. Hayflick accepted the position and moved
back to Philadelphia to work at the Wistar Institute.

 Since the
early 1900s, a predominant theory of cells in culture assumed that cells
 could multiply and grow forever. This assumption relied on the early
twentieth century studies of Alexis Carrel, a physician in France, whose work with chick
 hearts had convinced many that all cells were immortal. If cells failed
 to grow in the lab, researchers attributed the failure to unknown
nutritional conditions, to technicians incorrectly handling the cells,
or to contaminations in the glassware.

 At the Wistar Institute in 1958, Hayflick began to study whether or not viruses could cause cancers in humans.
 Hayflick cultured human cancer cells. He aimed to extract from them
viruses, hypothesized to cause cancer, that he could isolate by
introducing them into normal cells in culture. For this study, he needed
 to grow normal human cells not containing any viruses in a lab.
Hayflick used fetal human lung cells because, compared to adult cells,
they had a lower chance of containing viruses, and lung tissue allowed
for the formation of fibroblasts, or structural cells in the body.

 While
 he cultured twenty-five strains of fetal cells, Hayflick noticed that
some of the cultures stopped dividing after about 50 cell population
doublings. The cells were not dead, as they continued metabolizing, but
the cells did not divide. Hayflick published an article in 1961
detailing the results of these cell cultures titled "The serial
cultivation of human diploid cell strains."

 In 1965, Hayflick published "The limited *in vitro*
 lifetime of human diploid cell strains." In this article, Hayflick
notes that adult cells divide fewer times than do fetal cells, and that
the cause of this limited cell division isn't caused by a virus,
bacteria, or accounted for by error. Hayflick hypothesized in his
article that cellular aging
 could result from one or many targets or substances of cellular damage
and that the cells could hold intrinsic factors that determine aging.

 At
 the time of the 1965 experiment, Hayflick had established a cell
culture, the WI-38 strain, with fetal cells that Hayflick had acquired
from Sweden. Hayflick shipped these WI-38 cultures to many other
scientists, including Stanley Plotkin at the Wistar Institute, where the
 cells were later used for rubella vaccines. WI-38 cells began to be in
high demand during the 1960s.

 Despite Hayflick’s recognition for
 the WI-38 cultures, he remained in the same associate position at the
Wistar Institute, which was partially funded by the US National Institutes of Health
 (NIH) headquartered in Bethesda, Maryland. Koprowski had also created a
 guaranteed deal with SmithKline Beckman in the US and the Burroughs
Wellcome Company in the UK to purchase WI-38 cultures, as well as the
cell-culture technology that Hayflick created to produce a polio vaccine
 with the live, attenuated virus. Hayflick later said that he was
unhappy with Koprowski’s decision to sell the cells for profit.

 In 1968, Hayflick accepted a position as a professor of medical microbiology at Stanford University
 in Stanford, California. In Janurary of 1968, Hayflick met with
Kaprowski and representatives of the NIH and American Type Culture
Collection (ATCC), based in Rockville, Maryland, to discuss what would
occur with the remaining containers of WI-38 cells, as Hayflick would
soon be changing jobs. Those present at the meeting agreed to allow
Hayflick ten containers of the WI-38 cells, with ten of the remaining
WI-38 cultures placed at the Wistar Institute and the rest in the care
of the ATCC as property of the NIH. However, the NIH claimed that it
owned the cells and that only it could distribute and sell the cells
through the ATCC. Hayflick claimed to have title to own the cells, and
that the estate of the fetus also had an interest in the cells.

 Hayflick
 reported that he felt a sense of injustice, and he went to the Wistar
Institute and took all of the WI-38 samples before leaving for
California. He sent these cultures to scientists for the same price that
 the ATCC would have charged researchers for shipping the cells, and he
saved that money into a special account until a further decision on
ownership of the cells could be determined. In the spring of 1975,
Hayflick brought the issue of ownership to the NIH in hopes of settling
who owned the cells. Later that year, NIH accountants and some US
Department of Health, Education, and Welfare (DHEW) employees
investigated Hayflick. Under the 1966 US Freedom of Information Act, the
 NIH gave the accountant’s report to journalists who published it in
March of 1976. The report claimed that Hayflick had stolen and sold
property of the United States Government, and that he had mishandled the
 cells.

 Hayflick sued the NIH in 1975 to prevent the release of
the report and to gain the title to the WI-38 cells, arguing that the
report violated the 1974 US Privacy Act. A California court denied a
motion for preliminary injunction of the reports, and Hayflick followed
with an appeal in 1978, after the reports were released. The US Ninth
District Court of Appeals affirmed the previous decision, and they
dismissed the appeal. With tension growing from the release of the
reports, Hayflick left his job at Stanford in what he called a protest
to the behavior of the university leadership, and the NIH confiscated
his WI-38 cell cultures while Hayflick attended a conference. The issue
as to who had title to the WI-38 cells remained unresolved.

 In
late 1976, Hayflick accepted a position as a senior researcher at
Children’s Hospital Medical Center in Oakland, California. In 1977, the
NIH accepted Hayflick’s application for a grant for some money as well
as for WI-38 cells. Hayflick did not receive that grant or any WI-38
cells until January of 1981. Hayflick continued to ask for the title of
the WI-38 cells, and an out-of court settlement was offered by the US
Justice Department, the US Food and Drug Administration
 (FDA), NIH, and the DHEW in the summer of 1981. After some
modifications, Hayflick settled with the FDA, the NIH, and the DHEW, and
 he received title to six of the original containers of WI-38 cells. He
also received the ability to use the money, plus interest, from an
escrow account. He had opened the account at the start of the suit and
had deposited in it the money he’d received from distributing the WI-38
cells while at Stanford. Hayflick later said that all of that money paid
 litigation fees. After the settlement, eighty-five scientists filed a
letter in favor of Hayflick in the journal, *Science*. Hayflick and
 others claimed that it was through his efforts in asking for the title
to the WI-38 cells that helped US policy to evolve, and to allow
research institutions and scientists to receive title to new life forms,
 even when the research is federally funded.

 In his 1974 work, *Intrinsic Mutagenesis: a Genetic Approach to Ageing*, the Nobel Prize Laureate Frank MacFarlane Burnet called Hayflick’s account of cellular aging
 The Hayflick Limit. In 1981, Hayflick became director of the Center for
 Gerontological Studies in Gainesville, Florida, as well as professor at
 the University of Florida in Gainesville. In 1982, Hayflick became
president of the Gerontological Society of America in Washington D.C.

 In
 1988, Hayflick became a professor at the University of California in
San Francisco, California. In 1994, he published a book titled *How and Why We Age*.
 Hayflick received greater than twenty-five awards, authored greater
than two-hundred and fifty scientific works, and has participated in
various editing, government, and medical boards and councils. As of
2014, Hayflick serves on various scientific committees and is writing an
 autobiography while living in California.

## Sources

1. Boffey, Philip M. “The Fall and Rise of Leonard Hayflick, Biologist Whose Fight With U.S. Seems Over.” *New York Times*, January 19, 1982. http://www.nytimes.com/1982/01/19/science/the-falland-rise-of-leonard-hayflick-biologist-whose-fight-with-us.html (Accessed June 2, 2014).
2. Burnet, Macfarlane. *Intrinsic Mutagenesis*. Houten: Springer, 1974.
3. Carrel, Alexis. “On the permanent life of tissues outside of the organism.” *The Journal of Experimental Medicine* 15 (1912): 516–28. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2124948/pdf/516.pdf (Accessed June 2, 2014).
4. Daar, Abdallah, and Heather L. Greenwood. “A proposed definition of regenerative medicine.” *Journal of Tissue Engineering and Regenerative Medicine* 1 (2007): 179–84.
5. Cell Associates Inc v. National Institute of Health Department of Health. 579 F.2d 1155 (App. Div. 1978). https://law.resource.org/pub/us/case/reporter/F2/579/579.F2d.1155.76-1978.html (Accessed June 11, 2014).
6. Hayflick, Leonard, and Paul S. Moorhead. “The serial cultivation of human diploid cell strains.” *Experimental Cell Research* 25 (1961): 585–621.
7. Hayflick, Leonard. “The limited in vitro lifetime of human diploid cell strains.” *Experimental Cell Research* 37 (1965): 614–36.
8. Hayflick, Leonard. “Hayflick’s Reply (To Wade).” *Science* 202 (1978): 128–135.
9. Hayflick, Leonard. *How and Why We Age*. New York: Ballantine Books. 1994.
10. Hayflick, Leonard. “A Novel Technique for Transforming the Theft of Mortal Human Cells into Praiseworthy Federal Policy.” *Experimental Gerontology* 33: 191–207.
11. Hayflick, Leonard. "The future of ageing." *Nature* 408 (2000): 267–269.
12. Hayflick, Leonard. Web of Stories. July, 2011. http://www.webofstories.com/play/leonard.hayflick/1 (Accessed September 7, 2013).
13. Hayflick, Leonard. Email Communications with *Embryo Project Encyclopedia* Editors. June– July, 2014.
14. Jiang,

 Lijing. “Degeneration in Miniature History of Cell Death and Aging
Research in the Twentieth Century” PhD diss., Arizona State University,
2013. http://hdl.handle.net/2286/R.A.114558 (Accessed June 18, 2014).

1. “Life’s Limit.” *Radiolab*. June 14, 2007. http://www.radiolab.org/story/91563-lifes-limit/ (Accessed July 14, 2014).
2. Shay, Jerry W., and Woodring E. Wright. “Hayflick, his limit, and cellular ageing.” *Nature* Reviews Molecular Biology 1 (2000): 72–76.
3. Stevenson, Robert. “Dr. Leonard Hayflick’s Oral History.” http://history.nih.gov/archives/downloads/hayflicktranscript.pdf (Accessed June 11, 2014).
4. Strehler, Bernard L., et al. “Hayflick-NIH settlement.” *Science* 215 (1982): 240–242.
5. U.S. Freedom of Information Act of 1966. Public Law 89-487. http://www.gpo.gov/fdsys/pkg/STATUTE-80/pdf/STATUTE-80-Pg250.pdf (Accessed July 14, 2014).
6. U.S. Privacy Act of 1974, 5 U.S.C. Section 522a (1974). http://www.gpo.gov/fdsys/pkg/STATUTE-88/pdf/STATUTE-88-Pg1896.pdf (Accessed July 14, 2014).
7. Wade, Nicholas. “Hayflick’s Tragedy: The Rise and Fall of a Human Cell Line.” *Science* 192 (1976): 125–127.
8. Wadman, Meredith. “Medical Research: Cell division.” *Nature* 498 (2013): 422–6.
9. Watts, Geoff. “Profile: Leonard Hayflick and the Limits of Ageing.” *Lancet* 377 (2011): 2075.

#### Subject:

 Fetal Tissue; Hayflick, Leonard;;
Cells;; Cell populations;; Cell death;; Apoptosis;; Cell proliferation;;
 Cell cycle;; Cell division;; Cell culture;; Human cell culture;;
Carrel, Alexis, 1873-1944;; Biotechnology;; Aging;; Wistar Institute of
Anatomy and Biology; Fetal Tissue; Hayflick, Leonard;; Cells;; Cell
populations;; Cell death;; Apoptosis;; Cell proliferation;; Cell cycle;;
 Cell division;; Cell culture;; Human cell culture;; Carrel, Alexis,
1873-1944;; Biotechnology;; Aging;; Wistar Institute of Anatomy and
Biology; People