COS-1 Cells: A Cellular Workhorse in Gene Expression Studies

The COS-1 cell line is a fibroblast-like cell that originates from a monkey's kidney tissue and is frequently employed by researchers to investigate the monkey virus, SV40. These cells are readily transfected and often utilized to create recombinant proteins for various biochemical, molecular, and cell biology experiments.

This article will provide comprehensive details on the COS-1 cell line, covering all the essential information you need. Specifically, you will gain knowledge on the following:

COS-1 cell line: Origin and general information.
Pros and Cons of COS-1 cells
Research Applications of COS-1 Cells
COS-1 cells: Publications
Resources for the COS-1 cell line, including protocols, videos, and more
Culturing COS-1 cells

1. COS-1 cell line: Origin and general information.

Before commencing any work with a cell line, it is essential to have a fundamental understanding of the cell line itself. This includes information such as the origin of the cells, how they were isolated, and their characteristics. In this section, we will delve into the basics of COS-1 cells.

What is the COS-1 cell line?

The COS-1 cell line comprises fibroblast-like cells that J.W.F. Cowell and colleagues first created in 1981. These cells were generated by transforming a green monkey epithelial cell line known as CV-1 with a mutant form of the Simian Virus SV40. Subsequently, the established COS-1 cell line was thoroughly characterized to restore the region of the SV40 genome that had been previously deleted from the origin of replication. These cells express large T antigens and other proteins necessary to replicate circular genomes, such as plasmids correctly.

Chlorocebus aethiops (African green monkey)

COS-1 cells have a fibroblast-like morphology and adhere to surfaces, spreading out as a monolayer. There are currently no known genetic variants of the COS-1 cell line. However, a related cell line COS-7 also originated from CV-1 cells and displays similar characteristics.

2. Pros and Cons of COS-1 cells

The COS-1 cell line has unique advantages and limitations, which we will discuss below.

Advantages

Transfection amenability: The COS-1 cell line is readily transfected using various methods, including physical and chemical approaches.
Production of Lentiviruses: The COS-1 cell line is a suitable packaging host for producing high-quality recombinant lentivirus particles without additional purification steps. These cells firmly adhere to plastic surfaces, which prevents contamination of transfection supernatants containing viral particles [1].
Gene Expression: The COS-1 cell line is widely used for transient and stable expression analysis studies, producing many recombinant proteins via transfection with circular plasmids containing the SV40 origin of replication [2].

Limitations

Non-human cell line: As COS-1 cells originate from non-human primates, recombinant proteins produced by this cell line are only suitable for laboratory experiments and cannot be recommended for human use.

3. Research Applications of COS-1 Cells

One of the most critical considerations when discussing a cell line is its research applications. This section will explore the most prominent research applications of COS-1 cells.

Recombinant protein production: The COS-1 cell line is widely utilized for producing recombinant proteins through transient or stable transfection of circular vectors containing the SV40 origin of replication. In a recent study, biologists used the COS-1 cell line to produce equine chorionic gonadotropin, a recombinant reproductive hormone for reproductive applications [3]. Similarly, another study utilized COS-1 cells to produce a recombinant chickenized monoclonal antibody against a specific type of influenza virus [4].
Production of viral-like particles: COS-1 cells serve as packaging hosts for high-quality lentivirus production and can be utilized for generating viral vaccines. A study used the COS-1 cell line to produce non-infectious but highly immunogenic dengue virus-like particles, which are effective vaccine candidates [5].

4. COS-1 cells: Publications

Some notable publications on COS-1 cells are:

Production and Purification of Dengue Virus-like Particles from COS-1 Cells: This publication in Bio-Protocol explains the use of COS-1 cells for producing highly immunogenic dengue virus-like particles.
Expression analysis of recombinant equine chorionic gonadotropin in three host systems - E. coli BL21C, Sf insect cell lysate and COS-1 mammalian cells: In this study, researchers have compared the production and post-translational modification of a recombinant reproductive hormone e.g., equine chorionic gonadotropin in different expression systems including COS-1 mammalian cells.
Investigating tick-borne Flaviviral-like particles as a delivery system for gene therapy: This study used COS-1 cells for producing tick-borne encephalitis virus (TBEV) like particles. These particles are proposed as a shuttle to deliver required replicons (i.e. therapeutic genes).
Generation of a recombinant chickenized monoclonal antibody against the neuraminidase of H9N2 avian influenza virus: This article published in AMB Express journal used COS-1 cells to produce recombinant chickenized monoclonal antibodies against the neuraminidase of bird influenza virus type H9N2.
Detergent-free solubilization of human Kv channels expressed in mammalian cells: In this study, the COS-1 mammalian cell line was used to express human Kv channels for conducting some solubilization experiments.

COS-1 cells at high and low confluency

5. Resources for the COS-1 cell line, including protocols, videos, and more

Cell culture protocols

COS-1 cell culture: This link contains valuable information about COS-1 cell splitting, freezing, and thawing.
COS-1 cells: This link contains basic information about the COS-1 cell line.

Transfection protocols

Here are some sources describing the transfection method for COS-1 cells.

Transient transfection of COS-1 cells: This document is comprised of a protocol for transient transfection of the COS-1 cell line.

Videos related to COS-1 cell line

The following video resources can assist in obtaining general information on culturing, maintenance, and transfection of COS-1 cells.

Passaging cells: This video discusses basic culturing practices for mammalian cell lines.
Freezing adherent cells: This video contains information for freezing down adherent cell lines.
Transfection protocol: This video shows a procedure for transfecting mammalian cells.

6. Culturing COS-1 cells

Characteristic	Information
Doubling time	Approximately 48 hours
Adherent or in suspension	Adherent grows as a monolayer on the surface of the culture flask
Seeding density	2 to 4 x 10^4 cells/cm²; adherent cells are washed with 1x PBS, treated with Accutase, centrifuged, resuspended, and dispensed into a new flask
Growth medium	Dulbecco's Modified Eagle Medium (DMEM) containing 10% FBS; media should be replaced 2 to 3 times a week
Growth conditions (temperature, CO2)	Requires a humidified incubator with 5% CO2 and 37°C temperature
Storage	Below -150°C temperature in the vapor phase of liquid nitrogen
Freezing process and medium	A slow freezing method with a temperature decrease of only 1 °C using CM-1 or CM-ACF media
Thawing process	Thaw frozen cells by incubating them in a water bath set at 37°C for 40-60 seconds with rapid agitation. Centrifuge cells to remove the freezing medium, resuspend the pellet, and dispense into a culture flask with fresh media. Adhesion takes approximately 24 hours.
Biosafety level	Biosafety level 1 is recommended for handling COS-1 cells

We hope that this article has provided an ample amount of information to help you to start working with COS-1 cells. Please order from us if you want to use this cell line for your research study.

References

Smith, S.L. and T. Shioda, Advantages of COS-1 monkey kidney epithelial cells as packaging host for small-volume production of high-quality recombinant lentiviruses. Journal of virological methods, 2009. 157(1): p. 47-54.
MacKenzie, C.J. and T. Shioda, COS‐1 Cells as Packaging Host for Production of Lentiviruses. Current protocols in cell biology, 2011. 50(1): p. 26.7. 1-26.7. 15.
Bhardwaj, A., et al., Expression analysis of recombinant equine chorionic gonadotropin in three host systems: E. coli BL21C, Sf insect cell lysate and COS-1 mammalian cells. Indian Journal of Animal Research, 2021. 55(1): p. 40-45.
Wang, F., et al., Generation of a recombinant chickenized monoclonal antibody against the neuraminidase of H9N2 avian influenza virus. AMB Express, 2020. 10: p. 1-7.
Galula, J.U., G.-J.J. Chang, and D.-Y. Chao, Production and Purification of Dengue Virus-like Particles from COS-1 Cells. Bio-protocol, 2019. 9(12): p. e3280-e3280.