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Immortalized Cell Lines vs Primary Cells
Primary cells originate from living tissues which allows them to preserve physiological and genetic states to study intracellular functions and disease mechanisms. However, the primary cells are prone to the environment and short-lived. The primary cells are not suitable for long-term and large-scale experiments. Immortalized cell lines can be obtained from spontaneous or artificial mutations, which can be long-term. The immortalized cell lines are convenient for repeated experiments and have a long life. The genes in immortalized cell lines may be lost, and the biological activity is different from primary cells.
Creative Biolabs is a leading international biotechnology company that specializes in customized primary cells and immortalized cell lines. It serves customers by providing various cell models based on customer requirements. With its state-of-the-art technology and extensive experience, Creative Biolabs helps customers in biomedical research and drug development, and provides high quality and reliable cell models for experiments from in vitro to in vivo.
Basic Definitions and Classification of Cell Types
Primary Cells
Definition
Primary cells are a type of cell that is directly isolated from the living tissues of organs, peripheral blood, or embryos. The method of isolation includes enzymatic digestion (e.g. collagenase) or mechanical separation.
Characteristics
- Retain the biological and physiological properties of the source tissue, including gene expression and functional proteins.
- Limited proliferative capacity, typically undergoing senescence after a finite number of divisions.
Sources
Human or animal tissues, tumor samples, and other biological specimens.
Cell Lines
Definition
Cell lines are populations of cells derived from primary cells after the first successful passage. They are classified into:
- Finite Cell Lines: Cells that can be passaged for 40–50 generations before senescing and dying.
- Continuous/Immortalized Cell Lines: Gain unlimited proliferation capacity through spontaneous mutations, viral genes, or artificial induction.
Key Differences Between Primary Cells and Immortalized Cell Lines
Table 1 Differences between cell lines
| Characteristics | Primary cells | Continuous/immortalized cell lines |
| Origin | Directly isolated from living tissue | Converted from primary cells or tumor-derived |
| Lifespan and Proliferation Capacity | Limited division (≤10 generations), telomere shortening leading to senescence | Unlimited proliferation, exceeding the Hayflick limit |
| Genetic Stability | Maintains diploid genome, minimal genetic variation | Prone to genetic drift, chromosomal abnormalities (polyploidy) |
| Biological Relevance | High (simulates in vivo microenvironment) | Low (phenotype/function may deviate from source tissue) |
| Cultivation difficulty | Requires customized medium and strict conditions (prone to death) | Adaptable to standard conditions, easy to expand |
| Experimental Consistency | Donor differences lead to batch-to-batch variability | Highly uniform, high reproducibility |
| Cost and Time | High cost (time-consuming separation), slow proliferation | Low cost, rapid expansion |
Derivation and Maintenance Methods
Primary Cells
Derivation Methods
- Enzymatic digestion: Collagenase/trypsin degradation of extracellular matrix.
- Mechanical separation: Physical cutting of tissue followed by filtration and purification.
Maintenance Challenges
- Requires tissue-specific culture medium (e.g., endothelial cells require VEGF supplementation).
- Sensitive to oxygen concentration and matrix coating (e.g., collagen).
Immortalized Cell Lines
Immortalization Methods
- Viral genes: SV40 T antigen, EB virus.
- Telomerase activation: hTERT gene transfection to maintain telomere length.
Figure 1 Telomerase components and TERT structure.1,2
Advantages
- Can grow in basic culture media.
- Tolerant to freezing/thawing, suitable for establishing cell banks.
Molecular Mechanisms of Genetic Stability
Table 2 Genetic Stability of different cell types
| Cell type | Genetic characteristics | Molecular mechanisms |
| Primary cells | Diploid karyotype, retains the genome of the source tissue | No long-term culture stress, intact DNA repair mechanisms |
| Immortalized cell lines | Genetic drift, aneuploidy, chromosomal abnormalities |
Mechanisms include: - Telomere crisis leading to chromosome fusion - Oncogene-induced genomic instability |
Applications of Primary Cells and Immortalized Cell Lines
Primary Cells:
- Short-term physiological/pathological mechanism studies: Due to their retention of the physiological characteristics of the source tissue, primary cells are more suitable for experiments requiring high physiological relevance, such as disease mechanism research, drug screening, and toxicity testing.
- Personalized medicine: In cancer research, for example, using primary tumor cells derived from patients can more accurately simulate individual differences.
- Drug sensitivity testing: Primary cells, due to their high similarity to in vivo environments, are commonly used in drug sensitivity testing.
- Tissue engineering and regenerative medicine: Primary cells play a significant role in tissue repair and regeneration research, such as cardiomyocytes and neurons.
Immortalized Cell Lines:
- Long-term or Repeated Experiments: Due to their unlimited passage capacity, they are suitable for experiments requiring long-term stability and high-throughput screening, such as drug screening, gene editing, and protein expression studies.
- High-Throughput Screening: Immortalized cell lines grow rapidly and are easy to expand, making them suitable for large-scale drug screening and toxicity testing.
- Standardized research: In basic biological research, such as cell proliferation and signaling pathway analysis, immortalized cell lines provide stable experimental models.
- Disease model construction: For example, mouse lung fibroblast immortalized cells (MLF cells) are used for disease model construction and drug screening in idiopathic pulmonary fibrosis (IPF).
Comparison and Selection:
- Primary cells are more suitable for studies requiring high physiological relevance, such as drug development and disease mechanism research.
- Immortalized cell lines are more suitable for standardized, high-throughput experiments and long-term research.
Choosing Between Primary Cells and Immortalized Cell Lines
Table 3 Complementary Application Strategies
| Research Phase | Recommended Cell Type | Reason |
| Mechanism Exploration (Short Term) | Primary Cells | High physiological relevance |
| Drug Screening (High Throughput) | Immortalized Cell Lines | Low cost, high reproducibility |
| Preclinical Validation | Primary Cells + Immortalized Cells | Balance between efficiency and predictability |
Creative Biolabs provides different kinds of primary cell lines and immortalized cell lines that meet your needs for biomedical research. Primary cells are maintained with physiologically and genetically relevant characteristics from their tissues of origin, making them suitable for investigating disease mechanism and drug response. Our immortalized cell lines are genetically engineered and can be replicated without end date and have stable genetic content, which is the best choice for large-scale research and long-term experiments.
Creative Biolabs has rich experience in cell culture and stable cell line construction. We provide high-quality and well-characterized products, such as human and animal cells. Creative Biolabs combine the characteristics of primary cells and immortalized cell lines to assist you in obtaining stable, scalable, and physiologically relevant results. Contact us today for more information!
References
- Chalak, Mahla, et al. "Cell Immortality: In Vitro Effective Techniques to Achieve and Investigate Its Applications and Challenges." Life, vol. 14, no. 3, Mar. 2024, p. 417. DOI.org, https://doi.org/10.3390/life14030417.
- Distributed under Open Access license CC BY 4.0, without modification.
Created June 2025
For Research Use Only. Not For Clinical Use.