United States Patent 4,393,133: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
United States Patent 4,393,133, titled "Human hepatoma derived cell line, process for preparation thereof, and uses therefor," is a significant patent in the field of biomedical research, particularly in the areas of cell biology, toxicology, and virology. This patent, granted in 1983, describes the development and uses of human hepatoma cell lines, which have been instrumental in various scientific and medical applications.
Background and Context
The patent was filed in 1980 and granted in 1983, a period marked by rapid advancements in cell culture techniques and the increasing importance of in vitro models for biomedical research. The inventors derived the cell lines from human hepatoma tissues, which are tumors of the liver, to create stable and reproducible cell lines for research purposes[1][2].
Cell Lines Described
The patent focuses on two specific human hepatoma cell lines: Hep G2 and Hep 3B. These cell lines were derived from biopsies taken during surgical procedures.
- Hep G2: This cell line was derived from a 15-year-old Caucasian male from Argentina in 1975. It is notable for its ability to retain many characteristics of normal human hepatocytes, making it a valuable tool for metabolic studies and drug testing[1][4].
- Hep 3B: This cell line was derived from an 8-year-old black male from the United States in 1976. The cells from which Hep 3B was derived contained hepatitis B virus, as evidenced by the presence of HBV antigens[1].
Process for Preparation
The patent details the method for isolating, culturing, and maintaining these cell lines. This involves the initial isolation of cells from tumor tissues, followed by their cultivation in appropriate media. The process ensures the cells are viable, stable, and can be propagated indefinitely, which is crucial for long-term research applications[1].
Uses of the Cell Lines
The cell lines described in the patent have several key uses:
- Metabolic Studies: These cell lines are useful for screening potential carcinogens and mutagens, as well as for studying metabolic pathways similar to those in normal human liver cells[1].
- Viral Cultivation: The cell lines can be used for the cultivation of viruses, including hepatitis B virus, which is particularly relevant for Hep 3B[1].
- Toxicology and Drug Testing: The Hep G2 cell line, in particular, is widely used for testing the toxicity and efficacy of drugs due to its ability to mimic many functions of normal liver cells[4].
- Biomedical Research: These cell lines are valuable tools for various biomedical research applications, including the study of liver diseases and the development of liver assist devices[4].
Patent Claims
The patent includes several claims that define the scope of the invention:
- Cell Lines: The patent claims the specific cell lines Hep G2 and Hep 3B, as well as methods for their preparation and maintenance[1].
- Cultivation Methods: Claims include the processes for culturing these cell lines, including the use of specific media and conditions[1].
- Uses: The patent claims various applications of these cell lines, such as metabolic studies, viral cultivation, and drug testing[1].
Patent Landscape
The patent landscape surrounding US 4,393,133 is complex and reflects the evolving nature of biomedical research and patent law.
- Related Patents: Other patents, such as US 5,290,684, build upon the work described in US 4,393,133 by exploring further applications of the Hep G2 cell line, including its use in liver assist devices[4].
- Regulatory Environment: The patent was granted during a period of significant change in patent law, particularly with the establishment of the Federal Circuit in 1982, which aimed to stabilize and harmonize patent law in the United States[3].
Impact and Significance
The impact of US 4,393,133 is multifaceted:
- Biomedical Research: The cell lines described have been instrumental in numerous research studies, contributing significantly to our understanding of liver function, viral infections, and drug metabolism[1][4].
- Industrial Applications: These cell lines are used in various industrial settings, including pharmaceutical companies, for drug testing and development[4].
Criticisms and Challenges
While the patent has been highly influential, there are also challenges and criticisms:
- Ethical Considerations: The use of human tumor tissues raises ethical questions about the source of the materials and the consent of the donors[1].
- Patent Law Evolution: The patent has been part of broader discussions on patent law, particularly regarding the harmonization of U.S. patent laws with international standards and the role of the Supreme Court in shaping patent law[3].
Conclusion
United States Patent 4,393,133 represents a significant milestone in the development of human hepatoma cell lines and their applications in biomedical research. The patent's scope and claims have had a lasting impact on various fields, from toxicology and virology to drug development and liver disease research.
Key Takeaways
- Cell Lines: Hep G2 and Hep 3B are the two primary cell lines described in the patent.
- Uses: These cell lines are used for metabolic studies, viral cultivation, drug testing, and other biomedical research applications.
- Impact: The patent has significantly contributed to biomedical research and industrial applications.
- Patent Landscape: The patent is part of a broader landscape of biomedical patents and has influenced subsequent patents and research.
FAQs
Q: What are the main cell lines described in US 4,393,133?
A: The main cell lines are Hep G2 and Hep 3B, both derived from human hepatoma tissues.
Q: What are the primary uses of these cell lines?
A: The primary uses include metabolic studies, viral cultivation, and drug testing.
Q: Where are these cell lines available?
A: These cell lines are available from the American Type Culture Collection (ATCC) and The Wistar Institute of Anatomy and Biology[1].
Q: Do these cell lines carry hepatitis B virus?
A: Hep 3B cells contain hepatitis B virus, while Hep G2 cells do not[1][4].
Q: How have these cell lines impacted biomedical research?
A: They have significantly contributed to our understanding of liver function, viral infections, and drug metabolism, and are widely used in various research and industrial applications.
Sources
- US4393133A - Human hepatoma derived cell line, process for preparation thereof, and uses therefor - Google Patents
- Human hepatoma derived cell line, process for preparation thereof ... - PubChem
- Mastering Patent Claim Construction - Digital Commons @ Touro Law
- US5290684A - Permanent human hepatocyte cell line and its use in a liver assist device (LAD) - Google Patents
