Basic structure of a mammalian cell. DOI:10.3390/app131810029
Mammalian cells are eukaryotic cells derived from organisms in the mammalian class of animals. They are characterized by their nucleus, which houses the genetic material, and a variety of organelles that enable essential functions like energy production, protein synthesis, and waste management.
Mammalian Cell Lines and Their Importance
Mammalian cell lines are established cells that can grow and divide in laboratory conditions, providing a versatile platform for scientific and industrial applications. These cell lines are often derived from tissues of mammals and are grown in culture systems. Although they are more challenging to cultivate compared to simpler cell types like bacterial cells, their ability to replicate the native biological processes of mammals makes them invaluable.
Applications of Mammalian Cells
Recombinant Proteins and Antibodies: Mammalian cells are the preferred system for producing high-quality recombinant proteins and therapeutic antibodies. Their ability to perform native post-translational modifications, such as glycosylation, ensures that the proteins produced are functional and mimic those found in humans.
Gene Therapy and Vector Production: Mammalian cells are employed to create viral vectors and other delivery systems for gene therapy, providing a platform to study and treat genetic diseases.
Biopharmaceuticals: Clinically important proteins like erythropoietin (EPO), tissue plasminogen activator (tPA), and monoclonal antibodies are commonly produced in mammalian cells.
Scientific Research: Mammalian cell systems are critical tools for understanding gene function, protein expression, and cell physiology. They allow researchers to analyze transcription, translation, and protein processing in a context that closely resembles human biology.
Structural and Functional Protein Studies: Mammalian cells facilitate the production of proteins with correct folding and glycosylation, enabling detailed structural characterization and functional studies.
Production of Viral Antigens: The ability to produce viral proteins, such as prehepatitis B virus surface antigen, supports vaccine development and immunological research.
Unique Features of Mammalian Cells
Mammalian cells possess several advantages over simpler systems like yeast or bacterial cells. For instance, they can perform post-translational modifications, such as glycosylation, phosphorylation, and sulfation, which are critical for the proper function of many proteins.
Unlike yeast or bacterial systems, mammalian cells can also produce glycoproteins with complex antennary oligosaccharides that closely mimic human glycosylation patterns, as well as having mechanisms to ensure that only correctly folded and assembled proteins are secreted.
Challenges in Mammalian Cell Systems
Complex Cultivation Requirements: Mammalian cells require specific growth conditions and are sensitive to contamination and environmental changes.
Higher Costs: Culturing mammalian cells is more expensive than using simpler systems like E. coli or yeast due to specialized media and facilities.
Time-Consuming Processes: Producing recombinant proteins or antibodies in mammalian cells often takes longer than in bacterial systems.
Limited Solutions: Unlike bacterial systems, mammalian expression systems require significant customization and expertise to meet specific research or production needs.
Advances in Mammalian Cell-Based Systems
Recent advancements in mammalian cell biotechnology have addressed some of these challenges. The development of transformable cell lines, viral vectors, and scalable suspension cultures has streamlined the use of mammalian cells in industrial applications. Stable and transient expression systems allow researchers to tailor production based on the scale and complexity of the protein required.
Commonly Used Mammalian Cell Lines
Several mammalian cell lines have emerged as preferred hosts for protein production and research:
Chinese Hamster Ovary (CHO) Cells: Widely used for therapeutic protein production due to their ability to grow in suspension and perform human-like glycosylation.
HEK293 Cells: Popular for transient protein expression and viral vector production.
COS Cells: Ideal for short-term expression studies, particularly in gene verification.
NS0 Myeloma Cells: Commonly used for monoclonal antibody production.
