HeLa Cells – Definition, Characteristics, Significance, Applications

What Are HeLa Cells?

• HeLa cells, derived from the cervical tissue of Henrietta Lacks, have become an instrumental human cell line in the realm of biological and medical research. These cells, initiated in 1951, have the unique characteristic of being “immortal,” meaning they possess the ability to continuously divide and proliferate when supplied with the necessary nutrients. This trait is attributed to their cancerous nature, which allows them to bypass the typical cellular mechanisms that regulate cell division and lifespan.
• In a typical scenario, human cells have a predetermined lifespan, governed by intrinsic cellular programs. Once they reach a certain age or undergo a specific number of divisions, they are programmed to undergo apoptosis, a form of controlled cell death. However, cancer cells, like HeLa cells, have undergone mutations that render them resistant to these regulatory mechanisms. As a result, they can perpetually divide, given the right conditions.
• The inception of the HeLa cell line traces back to early 1951 when tissue samples were extracted from Henrietta Lacks during her treatment for cervical cancer. These samples, taken without her informed consent, were then cultured ex vivo, leading to the establishment of the first-ever immortal human cell line. The progeny of these initial cells, termed “daughter cells,” are still in existence today, serving as a testament to their enduring nature.
• The significance of HeLa cells in scientific research cannot be understated. They played a pivotal role in the development of the polio vaccine and were instrumental in the isolation of the human immunodeficiency virus (HIV). Their unique properties have facilitated countless breakthroughs, offering insights into cellular biology, genetics, and the development of therapeutic interventions for various diseases.
• However, the story of HeLa cells is not without its ethical quandaries. The fact that Henrietta Lacks’ tissue was procured without her explicit consent has sparked debates about the ethical implications of using human tissues for research. This has led to a paradigm shift in the way medical professionals approach tissue biopsies. In contemporary times, it is imperative that informed consent is obtained before procuring any tissue for research purposes, ensuring that the rights and autonomy of individuals are upheld.
• In summation, HeLa cells, while being a monumental asset to the scientific community, also serve as a poignant reminder of the ethical considerations that must be at the forefront of biomedical research. Their legacy is twofold: they have catalyzed advancements in medicine and biology, and they have underscored the importance of ethical integrity in scientific endeavors.

Definition of HeLa Cells

HeLa cells are an immortal human cell line derived from the cervical cancer tissue of a patient named Henrietta Lacks. First cultured in 1951, these cells have the unique ability to divide and proliferate indefinitely in vitro, making them invaluable for scientific and medical research. Their widespread use has contributed to numerous biomedical breakthroughs, though their origin has also raised significant ethical considerations regarding informed consent in medical research.

Brief History of the HeLa Cell

In the annals of medical research, few cell lines have garnered as much attention, both scientifically and ethically, as the HeLa cells. Their origin traces back to 1951 at the Johns Hopkins Hospital in Baltimore, where a 31-year-old African-American woman, Henrietta Lacks, sought medical attention for a lump in her cervix. Subsequent examinations diagnosed her with an aggressive form of cervical cancer, specifically adenocarcinoma. As part of her treatment, which involved radiation-tube implants or Brachytherapy, a sample of her cancerous tissue was extracted. This extraction, unbeknownst to Lacks, was not solely for therapeutic purposes.

Dr. George Otto Gey, the then Director of the Tissue Culture Laboratory at Johns Hopkins, had been on a quest to cultivate a sustainable human cell line for cancer research. While numerous attempts with other patients’ tissues had been unsuccessful, Lacks’s tissue sample proved to be an exception. The cells derived from her biopsy, later termed “HeLa” cells (an abbreviation of her name), exhibited an unprecedented ability to thrive in vitro. Remarkably, these cells doubled in number approximately every 20-24 hours, a rate of growth that was unusually rapid even for cancerous cells. This robust proliferation rendered HeLa cells an invaluable asset for large-scale scientific experiments.

The identity of the donor of these cells remained a mystery until the 1970s when it was publicly disclosed that they originated from Henrietta Lacks. Prior to this revelation, there were misconceptions that the cell line was named after a “Helen Lane” or “Helen Larson.”

HeLa cells’ unique “immortal” nature, which allows them to divide indefinitely under appropriate conditions, has led to their widespread use in biomedical research. However, their origin has not been without controversy. The fact that Lacks’s tissue was procured without her informed consent raised significant ethical concerns. Johns Hopkins Hospital, the institution where Lacks was treated, often used patients receiving free care, particularly from segregated sections of the hospital, as unwitting subjects for research. The Lacks family remained unaware of the extensive use and commercialization of HeLa cells and did not benefit financially from their widespread application.

The ethical dilemmas surrounding the HeLa cells culminated in legal and regulatory changes. The case of Moore v. Regents of the University of California in 1990 set a precedent that discarded tissues are not personal property and can be commercialized. However, in response to growing concerns about patient rights and privacy, the Common Rule was established in 1981, emphasizing informed consent and the de-identification of tissue samples.

The legacy of Henrietta Lacks and her HeLa cells took another turn in 2021 when her estate initiated legal actions against companies, including Thermo Fisher Scientific and Ultragenyx, for profiting from the unauthorized sale of HeLa cells. By 2023, settlements with some of these companies had been reached, though the terms remained undisclosed.

In summary, the history of the HeLa cell line is a testament to the intertwined nature of scientific advancement and ethical responsibility. While the cells have undeniably furthered our understanding of biology and medicine, their origin serves as a poignant reminder of the importance of informed consent and the rights of individuals in medical research.

Major Characteristics of HeLa Cells

HeLa cells, derived from the cervical tissue of Henrietta Lacks, have been a cornerstone in biomedical research due to their unique properties. Here are the major characteristics that set HeLa cells apart from other human cells:

1. Cancerous Nature:
   • HeLa cells originate from cancerous tissue, making them inherently different from typical human cells in terms of genetic makeup.
   • Genomic studies have revealed that HeLa cells possess numerous genetic anomalies. Unlike a standard human cell, which contains 46 chromosomes, HeLa cells have been found to harbor between 76 and 80 chromosomes, many of which are significantly mutated.
   • Recent investigations have identified the presence of Human Papillomavirus (HPV) DNA within HeLa cells. HPV is a leading causative agent of cervical cancer. It operates by integrating its DNA into the host cell’s genome. The integrated HPV DNA produces a protein that inhibits the function of p53, a crucial protein involved in DNA repair and tumor suppression. This interference leads to altered microRNA expression patterns, promoting the aggressive growth of HeLa cells in culture.
2. Rapid Growth Rate:
   • HeLa cells exhibit an exceptional growth rate, even when considering their cancerous nature. Their ability to double in number within a 24-hour period makes them particularly valuable for extensive research applications.
   • Their rapid proliferation also means that HeLa cells can easily contaminate and dominate other cell cultures, a factor researchers must be cautious of.
   • The accelerated growth of HeLa cells has been linked to the presence of both HPV and syphilis in Henrietta Lacks. The coexistence of these infections is believed to suppress the immune response, further facilitating the unchecked growth of these cells.
3. Immortality:
   • One of the most defining features of HeLa cells is their “immortality.” These cells possess the remarkable ability to undergo continuous division, a trait that has enabled their cultivation for over six decades.
   • The perpetual division of HeLa cells is largely attributed to the overexpression of telomerase, an enzyme responsible for maintaining the length of telomeres during cell division. By continuously rebuilding telomeres, HeLa cells evade the typical cellular aging process known as senescence, allowing them to divide indefinitely.

Why Are HeLa Cells Immortal?

• HeLa cells, a unique cell line derived from the cervical tissue of Henrietta Lacks, have been a focal point in biomedical research due to their “immortal” nature. But what grants these cells their immortality?
• At the core of cellular division and lifespan lies the intricate structure of DNA, specifically the telomeres. Telomeres are non-coding DNA sequences located at the ends of chromosomes, acting as protective caps. Analogous to the plastic tips on shoelaces, telomeres prevent the unraveling and degradation of chromosomal DNA. With each cell division, these telomeres experience a slight reduction in length. Once they reach a critical size, the cell’s ability to divide is hindered, leading to cellular senescence or programmed cell death, known as apoptosis.
• However, cancer cells, including HeLa cells, exhibit a deviation from this norm. Instead of experiencing telomere shortening, these cells possess the ability to maintain or even elongate their telomeres. This phenomenon can be attributed to the enzyme telomerase. Telomerase, composed of the protein enzyme telomerase reverse transcriptase (TERT) and an RNA component (TERC), facilitates the addition of telomere sequences, effectively counteracting the natural shortening process. While telomerase is expressed in certain cells, such as early sperm cell types, stem cells, and blastocysts, its elevated levels are particularly notable in cancer cells. This continuous telomere elongation grants cancer cells their characteristic unchecked division and growth.
• In the context of HeLa cells, the expression of genes responsible for telomerase production, specifically TERT and TERC, remains active, allowing these cells to continuously replenish their telomeres. This is a stark contrast to most normal cells, where telomerase expression is limited, leading to eventual telomere shortening and cell death.
• It’s worth noting that while HeLa cells are renowned for their immortality, they do not possess the longest telomeres among cancer cells. For instance, the U2OS cell line, derived from an osteosarcoma patient, has even longer telomeres. Nonetheless, the longevity of telomeres in HeLa cells surpasses that of many normal cells, especially as time and cellular divisions progress.
• The study of HeLa cells and their immortal nature has provided invaluable insights into the mechanisms of cancer cell growth. By understanding the role of telomerase and the genetic mutations that contribute to uncontrolled cell division, researchers are better equipped to develop targeted therapies. The ultimate goal is to selectively target and eliminate cancer cells without harming healthy cells, a challenge that remains at the forefront of oncological research.
• In summary, the immortality of HeLa cells is intricately linked to their ability to maintain telomere length through the sustained activity of telomerase. This unique characteristic not only sets them apart from normal cells but also offers a window into the molecular mechanisms underlying cancer cell proliferation.

The HeLa Cell Line

The HeLa cell line, derived from the cervical tissue of Henrietta Lacks, stands as a monumental entity in the realm of scientific research. Its widespread application has spanned numerous studies, each contributing uniquely to our understanding of biology and medicine.

1. Broad Spectrum of Applications:
   • The HeLa cell line has been a cornerstone in a myriad of scientific investigations. From being dispatched to space to discern the implications of zero gravity on human cells, to serving as a model for cosmetic ingredient testing, HeLa cells have been instrumental in advancing diverse research areas. Their role in understanding the interaction of COVID-19 with human cells and in cancer research underscores their continued relevance in contemporary biomedical studies.
2. Genetic Anomalies:
   • A distinguishing feature of HeLa cells is their chromosomal count. Unlike typical human cells that possess 46 chromosomes, HeLa cells exhibit between 76 to 80 chromosomes. This anomaly can be attributed to the human papillomavirus that afflicted Henrietta Lacks. Viral infections often involve the integration of viral DNA into host cells, which can disrupt normal cellular functions. In the case of the human papillomavirus, it produces a protein that impedes the cell’s inherent DNA repair mechanisms.
3. Immortality in Culture:
   • One of the defining characteristics of HeLa cells is their ability to perpetually divide under appropriate conditions. This immortality, rare among cell lines, has made them an invaluable asset in laboratories. Their continuous division, when adequately nourished, sets them apart from many other cell lines.
4. Rapid Proliferation:
   • While it’s a general notion that cancer cells do not necessarily grow faster than their normal counterparts, HeLa cells defy this convention. Originating from an aggressive form of cancer and further influenced by the syphilis that weakened Henrietta’s immune defenses, these cells exhibit an accelerated growth rate. This rapid proliferation has been particularly advantageous for researchers, allowing for expedited experimental outcomes.

In summation, the HeLa cell line, with its unique genetic makeup and unparalleled growth characteristics, has been a linchpin in the scientific community. Its contributions to diverse research areas, from virology to genetics, highlight its enduring significance in the ever-evolving landscape of biomedical research.

What are HeLa malignant growth cells?

HeLa cells have been a cornerstone in the realm of cancer research. These cells, distinguished by their rapid proliferation rate, surpass even the growth rate of typical cancer cells. A unique feature of HeLa cells, akin to many cancerous cells, is the active version of reverse telomerase they exhibit during cell division. This enzyme continually replicates telomeres, ensuring the cells’ longevity.

Genomically, HeLa cells present a myriad of anomalies. Unlike standard cells, which possess 46 chromosomes, HeLa cells harbor between 76 to 80 chromosomes, many of which are profoundly altered. This chromosomal aberration is a testament to the cells’ cancerous nature and their genetic instability.

The propensity of HeLa cells to contaminate other cell cultures has been a significant concern in scientific research. Their aggressive nature can compromise the integrity of other cell lines, rendering certain studies inconclusive or invalid.

HeLa cells have catalyzed numerous scientific breakthroughs, including:

1. Chromosome Counting: An inadvertent laboratory error in 1953 led to the relaxation of HeLa cell chromosomes, facilitating their clear observation and enumeration. This serendipitous event paved the way for the development of staining techniques, enabling accurate chromosome counting in human cells.
2. Virology: HeLa cells have served as experimental subjects for testing various viruses, elucidating their effects on human cells.
3. Laboratory Standards: The contamination challenges posed by HeLa cells underscored the need for stringent laboratory practices globally.
4. Understanding Cellular Longevity: Observations of HeLa cells have provided insights into the mechanisms by which certain cells maintain their youthfulness over extended periods.

However, the widespread use of HeLa cells has also sparked ethical debates, primarily centered around informed consent and patient privacy. Henrietta Lacks, the source of HeLa cells, never provided explicit consent for her cells to be employed in such expansive research. This situation underscored the imperative for robust guidelines to safeguard patient privacy and ensure the confidentiality of medical information.

Critical Research Advances Enabled by HeLa Cells

HeLa cells, first cultivated in 1952, have been instrumental in propelling the frontiers of biomedical research. These cells, renowned for their “immortality,” have been pivotal in numerous scientific breakthroughs, with their contributions spanning diverse areas of biology and medicine.

1. Polio Research: HeLa cells provided a robust platform for cultivating significant quantities of polioviruses, the causative agents of Poliomyelitis. This facilitated a deeper understanding of the virus’s mechanisms of infection and disease manifestation, laying the groundwork for the development of the polio vaccine.
2. Radiation Studies: In the nascent stages of radiation research, HeLa cells were employed to elucidate the detrimental effects of X-rays on human cell growth. These studies provided crucial insights into the potential health hazards associated with X-ray exposure.
3. Space Exploration: HeLa cells were among the first biological specimens to journey into space. These experiments offered preliminary data on how human cells might respond to space radiation, providing a foundation for understanding the potential challenges of prolonged space missions.
4. Therapeutic Advancements: HeLa cells played a pivotal role in investigating the therapeutic potential of Hydroxyurea against specific blood cancers and sickle cell anemia. The drug was observed to retard the growth of malignant cells and prevent the aberrant shaping of red blood cells in sickle cell anemia. Presently, Hydroxyurea is an approved treatment for certain hematological disorders.
5. Viral Mechanisms: Research on HeLa cells revealed that viruses like HIV and Ebola employ analogous mechanisms to infiltrate cells. This discovery, built upon prior HIV research, has been instrumental in the ongoing efforts to develop a more efficacious Ebola vaccine.
6. 6. Birth Defects and Thalidomide: HeLa cells were pivotal in deciphering the mechanisms through which the anti-nausea drug, thalidomide, caused birth defects. This understanding was subsequently harnessed to halt the progression of specific tumors, such as multiple myeloma.

In summary, HeLa cells have been at the forefront of over 110,000 scientific publications, underscoring their indispensable role in biomedical research. Their versatility and resilience have facilitated groundbreaking discoveries, shaping our understanding of human health and disease.

Henrietta Lacks – HeLa

• Henrietta Lacks, an African-American woman, navigated the challenges of racial disparities in the mid-20th century. Seeking medical attention for persistent abdominal discomfort, she consulted Dr. Howard Jones, who diagnosed her with cancer following a biopsy. Unbeknownst to Henrietta, a portion of her biopsy tissue was shared with Dr. George Gey, a prominent cancer researcher.
• In the realm of cell culture, achieving consistent growth of cells outside their native environment was a formidable challenge. However, Henrietta’s cells exhibited an unprecedented ability to thrive and multiply ex vivo. These cells, later named “HeLa” in homage to Henrietta Lacks, displayed an extraordinary proliferation rate, a characteristic that Dr. Gey capitalized on, cultivating them extensively even post Henrietta’s untimely demise at the age of thirty-one.
• The legacy of HeLa cells was shrouded in ethical dilemmas. Henrietta’s descendants remained oblivious not only to the extensive use of her cells in research but also to the public dissemination of her genomic data. It was only in 2013 that the National Institute of Health (NIH) stipulated controlled access to Henrietta’s genome, mandating acknowledgment of her family’s consent for researchers granted access. Concurrently, a landmark decision established that naturally occurring genes could not be patented, ensuring the sanctity of genetic material.
• While HeLa cells have catalyzed numerous scientific breakthroughs and generated substantial profits for entities leveraging them, Henrietta’s lineage has not been financially recompensed.
• The HeLa cell line stands as a dual testament: firstly, to the advancements in biomedical research, offering tools to combat ailments like the one that claimed Henrietta’s life; and secondly, to the evolution of ethical standards, ensuring individuals’ autonomy over their biological material, from tissues to individual cells.

Differences between ordinary cells and HeLa cells

Ordinary cells and HeLa cells exhibit distinct characteristics, which have been instrumental in the latter’s widespread use in scientific research. Here are the primary differences between these two cell types:

1. Growth Rate: HeLa cells possess an unusually rapid growth rate. Even when considering their cancerous nature, their proliferation is exceptional. In contrast, ordinary cells have a more regulated and slower growth rate.
2. Doubling Time: HeLa cells have a remarkable ability to double their cell count in a mere 24-hour period. This rapid doubling time is not characteristic of standard human cells.
3. Contamination Potential: Due to their aggressive growth, HeLa cells can easily contaminate other cell cultures. Their ability to outcompete and dominate other cell lines poses challenges in maintaining pure cell cultures in laboratory settings.
4. Immune System Interaction: Henrietta Lacks, the source of HeLa cells, had syphilis, which compromised her immune system. This weakened immune response likely contributed to the aggressive growth of the cancer cells in her body, a trait retained in the HeLa cell line.
5. Genetic Alterations: In 2013, it was elucidated that the genome of the Human Papillomavirus (HPV) had integrated near the c-Myc proto-oncogene in Henrietta’s genome. This integration led to the continuous expression of the c-Myc gene, further accelerating the replication of HeLa cells. Such specific genetic alterations are not present in ordinary cells.

Characteristic	Ordinary Cells	HeLa Cells
Growth Rate	Regulated and slower	Exceptionally rapid
Doubling Time	Varies, generally longer than 24 hours	Approximately 24 hours
Contamination Potential	Limited	High; can easily contaminate and dominate other cell cultures
Immune System Interaction	Standard immune interactions	Compromised due to syphilis in Henrietta Lacks, leading to aggressive growth
Genetic Alterations	Standard human genome without HPV insertion	HPV genome integrated near the c-Myc proto-oncogene, causing continuous expression of the c-Myc gene

In summary, while ordinary cells maintain a balanced growth and regulatory mechanism, HeLa cells, due to their unique genetic makeup and external factors, exhibit aggressive growth and replication characteristics. These differences have made HeLa cells both a boon and a challenge in the realm of scientific research.

Advantages of HeLa Cells

1. Immortality:
   • One of the most significant advantages of HeLa cells is their immortal nature. This allows for experiments to be conducted on identical cells, essentially clones of the original HeLa cells, ensuring consistency in research.
2. Medical Breakthroughs:
   • Over the past six decades, HeLa cells have been central to numerous medical advancements. Their unique properties have facilitated studies on the effects of toxins, cosmetics, radiation, and various chemicals on human cells, proving invaluable across multiple industries.
3. Space Research:
   • HeLa cells have contributed to space science. In the 1960s, they were sent to space in both Soviet and NASA satellites to study the effects of zero gravity on human cells. The findings revealed that cells divided more rapidly in zero gravity, offering insights into potential challenges of long-term space travel.
4. Gene Mapping:
   • HeLa cells played a pivotal role in the early stages of gene mapping. In 1965, researchers successfully fused HeLa cells with mouse cells, creating the first human-animal hybrid cell. This paved the way for understanding the human genome, as scientists could observe the proteins produced by the human gene within an animal context.

Disadvantage of HeLa Cells

1. Contamination Risk:
   • One of the major challenges with HeLa cells is their aggressive growth, which can lead to contamination of other cell cultures in a laboratory setting. This aggressive nature can skew research results, and many studies conducted on contaminated cell lines had to be discarded. Some laboratories even prohibit the use of HeLa cells to mitigate this risk.
2. Abnormal Karyotype:
   • HeLa cells do not possess a standard human karyotype. While a typical human cell contains 46 chromosomes, HeLa cells can have between 76 to 80 chromosomes, many of which are abnormal. This abnormality stems from the HPV infection that led to the cancer in Henrietta Lacks. As a result, HeLa cells are not entirely representative of normal human cells, limiting their applicability in certain research contexts.
3. Ethical Concerns:
   • The origin of HeLa cells, taken without the consent of Henrietta Lacks, has raised significant ethical issues regarding patient rights and informed consent in medical research.

In conclusion, while HeLa cells have undeniably revolutionized biomedical research due to their unique properties, they also come with challenges that researchers must consider. Balancing the benefits with the potential pitfalls is crucial for the continued responsible use of HeLa cells in scientific endeavors.

Significance of HeLa Cells

HeLa cells, derived from the cervical cancer tissue of Henrietta Lacks in 1951, have left an indelible mark on the landscape of biomedical research. Their significance spans multiple dimensions:

1. Pioneering Immortal Cell Line:
   • HeLa cells were the first human cells to be successfully cultured and maintained outside the human body for an extended period. Their “immortal” nature, characterized by their ability to divide indefinitely in a laboratory setting, made them a revolutionary tool for researchers.
2. Medical Advancements:
   • HeLa cells have been instrumental in numerous medical breakthroughs. They played a pivotal role in the development of the polio vaccine by Dr. Jonas Salk in the 1950s. Additionally, they have been central to research in cancer, virology, and even the human genome project.
3. Drug Testing and Development:
   • Their consistent growth and reproducibility have made HeLa cells a preferred choice for drug testing and development. They have been used to understand drug mechanisms, toxicity, and potential therapeutic effects.
4. Genetic Research:
   • HeLa cells have been foundational in the field of genetics. They have facilitated studies on gene expression, regulation, and the mechanics of DNA replication.
5. Ethical Discussions:
   • The story of Henrietta Lacks and the use of her cells without her knowledge or consent has sparked significant ethical debates. It has led to a reevaluation of patient rights, informed consent, and the use of human tissues for research. The discussions initiated by the HeLa cell story have contributed to the establishment of more stringent ethical guidelines and regulations in biomedical research.
6. Space Exploration:
   • HeLa cells were among the first human cells to be sent into space. Researchers aimed to understand the effects of zero gravity on human cells, providing insights into the challenges of long-term space travel.
7. Economic Impact:
   • The widespread use of HeLa cells in research has led to the commercialization of the cell line. They have been bought, sold, and distributed globally, leading to the growth of a multi-million dollar industry.
8. Cultural and Social Impact:
   • The story of Henrietta Lacks and HeLa cells has transcended the realm of science. It has been the subject of books, documentaries, and discussions, highlighting issues of race, class, and medical ethics.

In summary, the significance of HeLa cells is multifaceted. They have not only accelerated scientific discoveries but have also instigated important discussions on ethics, patient rights, and the broader implications of biomedical research. The legacy of HeLa cells serves as a testament to their unparalleled impact on science and society.

Microscopy of HeLa Cells

Microscopy plays a pivotal role in visualizing cellular structures and understanding their intricate details. HeLa cells, given their significance in biomedical research, have been a subject of microscopic studies for decades. Here’s a structured approach to observe HeLa cells, particularly their mitochondria, using light microscopy:

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Materials Required:

• Eagle’s medium
• Formaldehyde
• Cacodylate buffer
• Distilled water
• DAB (Diaminobenzidine) incubation medium
• Osmium tetroxide
• Light or electron microscope
• Glass slides
• Glass covers

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Procedure:

1. Cell Preparation:
   • Begin by washing the cultured HeLa cells with Eagle’s medium to remove any contaminants.
2. Cell Fixation:
   • Fix the cells by immersing them in formaldehyde for approximately 10 minutes. This step is crucial to preserve cellular structures and is typically conducted at a temperature of about 4°C.
3. Washing:
   • After fixation, wash the cells thrice using a solution of 0.44M sucrose in cacodylate buffer. This step ensures the removal of excess formaldehyde and prepares the cells for subsequent treatments.
4. DAB Incubation:
   • Subject the cells to the DAB incubation medium for around 3 hours. DAB acts as a chromogen, aiding in the visualization of cellular components.
5. Secondary Washing:
   • Post DAB treatment, rinse the cells twice at room temperature using a solution of sucrose in Tris buffer.
6. Osmium Tetroxide Treatment:
   • Treat the cells with osmium tetroxide for about an hour. This step enhances the contrast of cellular structures, making them more discernible under the microscope.

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Observation:

• Once the cells have undergone the above treatments, they are ready for microscopic observation. Place a small sample on a glass slide, cover with a glass cover, and observe under a light or electron microscope.

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This methodological approach ensures that HeLa cells, especially their mitochondria, are distinctly visible, facilitating a deeper understanding of their morphology and internal structures.

Applications of HeLa Cells

HeLa cells, derived from the cervical cancer cells of Henrietta Lacks, have been instrumental in numerous scientific breakthroughs and have a wide range of applications in biomedical research. Here are some of the prominent applications of HeLa cells:

1. Polio Vaccine Development: HeLa cells were pivotal in the development of the polio vaccine by Dr. Jonas Salk in the 1950s. They provided a consistent medium for the replication of the poliovirus, which was then used to develop the vaccine.
2. Cancer Research: Given their origin from a cervical tumor, HeLa cells have been extensively used in oncology research to understand cancer cell biology, mechanisms of tumor growth, and potential therapeutic interventions.
3. Drug Testing: HeLa cells serve as a model system for testing the effects of new drugs, especially their efficacy and potential toxicity.
4. Human Genetics: HeLa cells were the first human cells to be successfully cloned in 1955, paving the way for advancements in human genetics and the understanding of cellular mechanisms.
5. Virology: HeLa cells have been used to study the life cycle of various viruses, their interaction with host cells, and the development of antiviral drugs.
6. Effects of Radiation: Researchers have used HeLa cells to study the effects of radiation on human cells, which has implications for cancer treatment and understanding radiation poisoning.
7. Toxicology Studies: HeLa cells are used to study the effects of various toxins on human cells, aiding in the development of safety protocols and treatments for poisonings.
8. Space Research: HeLa cells were sent to space to study the effects of zero gravity on human cells, providing insights into how space travel might impact human health.
9. Enzyme Research: The behavior of various enzymes, especially those involved in DNA replication and repair, has been studied using HeLa cells.
10. Telomerase Studies: HeLa cells, with their immortal nature, have been instrumental in the study of telomerase (an enzyme that rebuilds telomeres) and its role in aging and cancer.
11. Study of HPV: Given that Henrietta Lacks’ cancer was caused by the human papillomavirus (HPV), HeLa cells have been used to study the lifecycle and pathology of HPV, leading to a better understanding of the virus and the development of the HPV vaccine.
12. Ethical Studies: The story of HeLa cells has also sparked discussions and studies on ethics, patient rights, and informed consent in scientific research.

In summary, HeLa cells have been a cornerstone in various fields of biomedical research, leading to significant advancements in medicine and biology. Their widespread use underscores their importance in understanding human health and disease.

Quiz

What is the origin of the name “HeLa” cells?
a) Derived from “Helix” because of their DNA structure.
b) Named after the scientist who discovered them, Dr. Helen Larsson.
c) An abbreviation of Henrietta Lacks, the woman from whom the cells were taken.
d) A Latin term meaning “immortal”.

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Why are HeLa cells considered “immortal”?
a) They have an infinite lifespan.
b) They can divide indefinitely under appropriate conditions.
c) They are resistant to all diseases.
d) They can regenerate any tissue.

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How many chromosomes do HeLa cells typically contain?
a) 23
b) 46
c) 76 to 80
d) 92

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Which virus’s DNA was found in HeLa cells?
a) HIV
b) Influenza
c) HPV (Human Papillomavirus)
d) Hepatitis B

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Which enzyme is overactive in HeLa cells, contributing to their immortality?
a) Lysozyme
b) Telomerase
c) Catalase
d) Amylase

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In which year were HeLa cells first isolated?
a) 1941
b) 1951
c) 1961
d) 1971

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HeLa cells have been instrumental in the development of which vaccine?
a) Measles
b) Polio
c) Tuberculosis
d) Mumps

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What type of cancer did Henrietta Lacks have from which HeLa cells were derived?
a) Breast cancer
b) Lung cancer
c) Cervical cancer
d) Ovarian cancer

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Which organization agreed in 2013 to release Henrietta’s genome sequence on an application basis only?
a) World Health Organization (WHO)
b) Centers for Disease Control and Prevention (CDC)
c) National Institute of Health (NIH)
d) Food and Drug Administration (FDA)

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Which of the following is a significant issue with HeLa cells in laboratories?
a) They are too fragile.
b) They can aggressively contaminate other cell cultures.
c) They require special growth mediums.
d) They are sensitive to light.

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FAQ

References

1. 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.
2. Masters, John R. (2002). “HeLa cells 50 years on: The good, the bad and the ugly”. Nature Reviews Cancer. 2 (4): 315–319.
3. 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.
4. Skloot, Rebecca (2010). The Immortal Life of Henrietta Lacks. New York: Crown/Random House.
5. 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.