The study of infectious diseases has relied heavily on immortalised cell lines to uncover how viruses and pathogens interact with human cells. From understanding viral entry mechanisms to developing vaccines and antiviral therapies, these models provide reproducible and scalable systems for research. While animal models remain important, cell lines allow researchers to dissect host–pathogen dynamics at the cellular level, reducing ethical concerns and enabling high-throughput experimentation.
This article explores ten of the most influential cell lines in virology, tracing their role in infectious disease research and their contributions to the development of therapies and vaccines.
HeLa Cells and Viral Replication Studies
Since their introduction in 1951, HeLa cells have been a cornerstone in virology. Their immortal nature and rapid division make them an excellent platform for studying viral replication cycles.
HeLa cells were instrumental in:
- Poliovirus research, which led to the development of the first polio vaccines.
- DNA tumour viruses, including insights into human papillomavirus (HPV) and its role in cervical cancer.
- HIV entry studies, where HeLa-based systems were used to characterise viral fusion processes.
Their resilience allows them to withstand infection with a wide variety of viruses, making them one of the most frequently employed lines for basic virology and vaccine testing.
HEK293 and Viral Vector Development
The role of HEK293 cells in virology cannot be overstated. Originally derived from human embryonic kidney tissue, these cells are highly permissive to viral transfection, making them ideal for producing viral vectors.
They are central to:
- Gene therapy, where adenoviral and lentiviral vectors produced in HEK293 cells deliver therapeutic genes.
- Vaccine development, as HEK293-based systems support scalable production of viral proteins.
- Viral entry mechanisms, allowing detailed study of receptor–virus interactions.
By serving as a reliable host for engineered viruses, HEK293 cells underpin both experimental virology and clinical applications in gene-based therapies.
CHO Cells and Viral Safety in Biologics
Though CHO cells are best known for biopharmaceutical production, their role in infectious disease research lies in ensuring viral safety of biologics. Because biologics are often derived from mammalian systems, they must be carefully screened for viral contamination.
CHO cells contribute by:
- Testing viral clearance protocols in manufacturing pipelines.
- Producing viral antigens for use in diagnostic assays.
- Studying host–virus interactions relevant to protein processing pathways.
Their adaptability in large-scale culture also allows CHO cells to support bioproduction of viral vaccines under controlled, safe conditions.
SH-SY5Y and Neurotropic Viruses
The neuroblastoma-derived SH-SY5Y line has become essential for studying viruses that affect the nervous system. These cells can be differentiated into neuron-like phenotypes, making them suitable models for neurotropic pathogens.
Researchers have used SH-SY5Y to investigate:
- Poliovirus replication in neuronal contexts.
- Herpes simplex virus latency and reactivation, providing insights into neuroinvasion.
- Neurotropic flaviviruses, such as Zika virus, which disrupts neuronal development.
By mimicking key aspects of neuronal physiology, SH-SY5Y cells support virology studies that focus on how viruses exploit the nervous system.
MCF7 and Viral Oncogenesis
Although primarily used in cancer research, MCF7 cells provide a valuable platform for studying viral oncogenesis. Their oestrogen receptor positivity makes them a model for hormone-responsive pathways influenced by viruses.
Applications include:
- Studying retroviral integration into hormone-responsive genomic regions.
- Exploring viral transformation mechanisms in epithelial cancers.
- Testing antiviral drugs that may alter oncogenic pathways.
MCF7 cells bridge the gap between virology and oncology, highlighting how viral infections can contribute to hormone-driven tumour development.
THP1 and Host–Pathogen Interactions
The monocytic THP1 line is invaluable in infectious disease research because of its capacity to differentiate into macrophage-like cells. As macrophages are critical players in innate immunity, THP1 models provide insight into how pathogens interact with the immune system.
They have been widely used to:
- Study HIV replication in monocyte-derived macrophages.
- Investigate tuberculosis pathogenesis, modelling macrophage infection by Mycobacterium tuberculosis.
- Assess immune activation in response to bacterial and viral toxins.
THP1 cells represent one of the most reliable surrogates for human immune responses in infectious disease modelling.
A2780 and Viral Chemotherapy Interactions
The ovarian carcinoma line A2780 has been used not only in oncology but also in exploring how viral infections influence chemotherapy responses. Viral oncolysis, where viruses selectively kill tumour cells, is a growing field of research.
A2780 cells contribute by:
- Testing oncolytic viruses that target ovarian cancer.
- Exploring synergy between chemotherapy and viral infection, which can improve therapeutic outcomes.
- Studying virus-induced resistance mechanisms, relevant to persistent infections.
These applications place A2780 at the intersection of virology and therapeutic innovation.
HL-60 and Viral Effects on Blood Cells
Promyelocytic HL-60 cells provide a useful model for studying viruses that target the haematopoietic system. Their ability to differentiate into granulocytes or monocytes allows researchers to simulate viral effects on developing blood cells.
They are applied in:
- Retrovirus studies, particularly how viral integration alters differentiation.
- Leukaemia-associated viruses, such as human T-cell leukaemia virus (HTLV).
- Immunosuppressive virus research, where HL-60 cells reveal how pathogens impair myeloid development.
This line contributes to understanding how viral infections disrupt blood cell formation and immune competence.
Caco-2 and Enteric Viruses
The colon carcinoma-derived Caco-2 line is essential for gastrointestinal virology. When differentiated, Caco-2 cells mimic enterocytes, making them a valuable system for studying enteric viruses.
Research has focused on:
- Norovirus and rotavirus infection, exploring viral entry and replication.
- Vaccine evaluation, using Caco-2 as a platform for testing attenuated strains.
- Intestinal immune responses, particularly barrier disruption during viral infections.
Because they replicate the intestinal barrier, Caco-2 cells are among the most relevant models for studying enteric pathogens.
HepG2 and Hepatitis Viruses
The HepG2 hepatocellular carcinoma line is one of the most widely used in hepatology and virology. Its hepatic nature makes it indispensable for studying hepatitis viruses and antiviral drug development.
HepG2 cells have been pivotal in:
- Hepatitis B and C virus research, clarifying mechanisms of viral replication.
- Antiviral drug testing, particularly nucleoside analogues that inhibit viral polymerases.
- Liver tropism studies, revealing how viruses exploit hepatic pathways.
Although not metabolically identical to primary hepatocytes, HepG2 cells remain central to hepatotropic virus research and antiviral development.
Conclusion
Cell lines have played a defining role in virology and infectious disease research. HeLa enabled polio vaccine development, HEK293 advanced viral vector production, and CHO supported safe biologics. SH-SY5Y illuminated neurotropic viruses, MCF7 contributed to viral oncogenesis studies, and THP1 modelled host–pathogen immune interactions. A2780 has been used in oncolytic virology, HL-60 in viral haematology, Caco-2 in enteric infections, and HepG2 in hepatitis research.
Together, these models provide reproducible, scalable, and ethically viable systems for investigating viruses. Their ongoing use ensures that discoveries in virology continue to shape vaccines, antivirals, and our preparedness for emerging infectious diseases.