HeLa cells are the first immortal human cell line. The cell line grew from a sample of cervical cancer cells taken from an African-American woman named Henrietta Lacks on February 8, 1951. The lab assistant responsible for the samples named cultures based on the first two letters of a patient's first and last name, thus the culture was dubbed HeLa. In 1953, Theodore Puck and Philip Marcus cloned HeLa (the first human cells to be cloned) and freely donated samples to other researchers. The cell line's initial use was in cancer research, but HeLa cells have led to numerous medical breakthroughs and nearly 11,000 patents.
Key Takeaways: HeLa Cells
- HeLa cells are the first immortal human cell line.
- The cells came from a cervical cancer sample obtained from Henrietta Lack in 1951, without her knowledge or permission.
- HeLa cells have led to many important scientific discoveries, yet there are disadvantages to working with them.
- HeLa cells have led to the examination of the ethical considerations of working with human cells.
What It Means to Be Immortal
Normally, human cell cultures die within a few days after a set number of cell divisions via a process called senescence. This presents a problem for researchers because experiments using normal cells cannot be repeated on identical cells (clones), nor can the same cells be used for extended study. Cell biologist George Otto Gey took one cell from Henrietta Lack's sample, allowed that cell to divide, and found the culture survived indefinitely if given nutrients and a suitable environment. The original cells continued to mutate. Now, there are many strains of HeLa, all derived from the same single cell.
Researchers believe the reason HeLa cells don't suffer programmed death is because they maintain a version of the enzyme telomerase that prevents gradual shortening of the telomeres of chromosomes. Telomere shortening is implicated in aging and death.
Notable Achievements Using HeLa Cells
HeLa cells have been used to test the effects of radiation, cosmetics, toxins, and other chemicals on human cells. They have been instrumental in gene mapping and studying human diseases, especially cancer. However, the most significant application of HeLa cells may have been in the development of the first polio vaccine. HeLa cells were used to maintain a culture of polio virus in human cells. In 1952, Jonas Salk tested his polio vaccine on these cells and used them to mass-produce it.
Disadvantages of Using HeLa Cells
While the HeLa cell line has led to amazing scientific breakthroughs, the cells can also cause problems. The most significant issue with HeLa cells is how aggressively they can contaminate other cell cultures in a laboratory. Scientists don't routinely test the purity of their cell lines, so HeLa had contaminated many in vitro lines (estimated 10 to 20 percent) before the problem was identified. Much of the research conducted on contaminated cell lines had to be thrown out. Some scientists refuse to allow HeLa in their labs in order to control the risk.
Another problem with HeLa is that it doesn't have a normal human karyotype (the number and appearance of chromosomes in a cell). Henrietta Lacks (and other humans) have 46 chromosomes (diploid or a set of 23 pairs), while the HeLa genome consists of 76 to 80 chromosome (hypertriploid, including 22 to 25 abnormal chromosomes). The extra chromosomes came from the infection by human papilloma virus that led to cancer. While HeLa cells resemble normal human cells in many ways, they are neither normal nor entirely human. Thus, there are limitations to their use.
Issues of Consent and Privacy
The birth of the new field of biotechnology introduced ethical considerations. Some modern laws and policies arose from ongoing issues surrounding HeLa cells.
As was the norm at the time, Henrietta Lacks was not informed her cancer cells were going to be used for research. Years after the HeLa line had become popular, scientists took samples from other members of the Lacks family, but they did not explain the reason for the tests. In the 1970s, the Lacks family was contacted as scientists sought to understand the reason for the aggressive nature of the cells. They finally knew about HeLa. Yet, in 2013, German scientists mapped the entire HeLa genome and made it public, without consulting the Lacks family.
Informing a patient or relatives about the use of samples obtained via medical procedures was not required in 1951, nor is it required today. The 1990 Supreme Court of California case of Moore v. Regents of the University of California ruled a person's cells are not his or her property and may be commercialized.
Yet, the Lacks family did reach an agreement with the National Institutes of Health (NIH) regarding access to the HeLa genome. Researchers receiving funds from the NIH must apply for access to the data. Other researchers are not restricted, so data about the Lacks' genetic code is not completely private.
While human tissue samples continue to be stored, specimens are now identified by an anonymous code. Scientists and legislators continue to wrangle with questions of security and privacy, as genetic markers may lead to clues about an involuntary donor's identity.
References and Suggested Reading
- Capes-Davis A, Theodosopoulos G, Atkin I, Drexler HG, Kohara A, MacLeod RA, Masters JR, Nakamura Y, Reid YA, Reddel RR, Freshney RI (2010). "Check your cultures! A list of cross-contaminated or misidentified cell lines". Int. J. Cancer. 127 (1): 1-8.
- Masters, John R. (2002). "HeLa cells 50 years on: The good, the bad and the ugly". Nature Reviews Cancer. 2 (4): 315-319.
- Scherer, William F.; Syverton, Jerome T.; Gey, George O. (1953). "Studies on the Propagation in Vitro of Poliomyelitis Viruses". J Exp Med (published May 1, 1953). 97 (5): 695-710.
- Skloot, Rebecca (2010). The Immortal Life of Henrietta Lacks. New York: Crown/Random House.
- Turner, Timothy (2012). "Development of the Polio Vaccine: A Historical Perspective of Tuskegee University's Role in Mass Production and Distribution of HeLa Cells". Journal of Health Care for the Poor and Underserved. 23 (4a): 5-10.