13.01.2022 duration: 5 min

HEK293 cells vs. CHO cells

HEK cells, also known as HEK293, are human embryonic kidney cells which grow in tissue culture and represent a distinct immortalised cell line. Although HEK cells and CHO cells are both used to create antibodies and for therapeutic protein production, they differ in many aspects, which will be discussed later in this article.

HEK cells – an overview

HEK cells, also known as HEK293 cells or human embryonic kidney cells, are widely known as one of the most important mammalian transient production platforms. The human embryonic kidney cells were originally a derivative from an aborted fetus and have since been in use in cell biology and biotechnology. They can be grown as adherent or suspension, but adherent is the more common choice.

One of the main reasons for their popularity is that HEK cells have a high transfection efficiency. Additionally, HEK293 cells are receptive to a wide range of transfection methods and can be used to create viruses for gene therapies, antibodies, therapeutic proteins and for safety tests of several chemicals.

History of human embryonic kidney cells

HEK293 cells were first isolated in 1973 by Alex van der Eb in the Netherlands. Cell cultures of human embryonic kidney cell lines were transfected with sheared adenovirus 5 DNA by Frank Graham. 

After the extraction, the HEK cells were cultured and the transfection with the adenovirus began. Cultured over months, the cells supposedly adapted to tissue culture and developed into a rather solid HEK293 line. It was assumed for many years that the HEK cells were generated by transforming fibroblastic, endothelial or epithelial cells. Yet, as the original transformation of the adenovirus was not efficient, it can be suspected that the cell was somehow special

A study of HEK293’s transcriptomes and genomes showed that the HEK-cell-pattern had the most similarities with adrenal cells. By now, many variants of HEK293 have been found such as HEK293T cells.

Application of HEK293 cells

The transfectability of the HEK293 cell line is the main reason for its widespread usage. HEK cells are easy to transfect and to grow in culture and can serve as hosts for experiments in gene expression. Most commonly, such experiments revolve around transfecting in a gene to analyze the expressed protein. This method can be used, for instance, for heterologous expression of cell membrane receptors and ion channels, to study the interaction between two proteins, to research the inducible RNA interference system, or to find out the effects a drug has on sodium-channels, to name a few.

The use of HEK cells in the propagation of adenoviral vectors is particularly significant. Due to its lack of key genes and inability to replicate itself after entering a cell, the usage of HEK cells instead of pathogens is safer for the researcher. Consequently, possibly harmful events can be prevented.

CHO cells – an overview

Chinese hamster ovary (CHO) cells are a widely popular cell line in the production of biologics and were originally derived from the ovary of the Chinese hamster, hence the name.

CHO cells are very similar to the human cell system and are therefore the most commonly used cell line derived from a mammalian host in medical and biological research, e.g.,. in toxicity screening, nutrition studies, genetic studies and gene expression.

One major objective of CHO cells is to express recombinant proteins. With the production capacity of 3-10 grams per liter of CHO cell culture, they have an outstanding protein productivity. Additionally, they are known for their long track record, robust growth and hardiness in suspension culture.

Chinese hamster ovary cells are a popular choice in the efficient production of:

  • Biotherapeutics
  • Antibodies (particularly recombinant antibodies)
  • APIs (active pharmaceutical ingredients)
HEK293 cells vs. CHO cells - evitria

HEK & CHO mammalian cell lines in comparison

Mammalian cells have a long history of being used for the production of recombinant protein therapeutics, especially CHO cells and HEK cells. While CHO cells are the most commonly used cell line, HEK293 cells are also known to be the go-to for many researchers. As the CHO cells stem from the Chinese hamster, the HEK cells are more considerable for some studies because of their human cell line origin. 

Yet, HEK293 and CHO cells are not the only possible options. There are also baby hamster kidney cells (BHK), NS0 murine myeloma cells, SP2/0 murine hybridoma cells, HT-1080 human fibrosorcoma cells as well as C127 murine mammary gland cells. Nonetheless, CHO mammalian cell lines in particular, but also HEK cells, are the cell lines of choice when it comes to protein production, as they offer distinct advantages over all of the above. ​1​

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    Advantages of HEK cell lines

    HEK cells are known for their high transfectability, but they also have other impressive characteristics:

    • Ability to generate glycosylation profiles of human kind 
    • High reproducibility
    • They can easily be manipulated
    • HEK293 can produce exogenous proteins
    • Many transfection methods available and they are able to be utilized for stable and transient gene expression
    • Multiple experiments possible, e.g., adenoviral-based vectors, can be conducted by using HEK293 cells

    However, the HEK cell line also has its limitations. In some cases, it is possible that the usage of HEK cells for protein production causes the final product to be contaminated. The production of stable recombinant protein with HEK cells has mostly been achieved by using xenogeneic genes as selection markers. This makes them prone to bacterial and to viral contamination, which could either result in immunogenicity to the product or in adverse and allergic reactions.

    Advantages of CHO cell lines

    CHO cells are an extraordinary bioprocess tool and are known to be the gold standard in biologics production because of their unique advantages. Some of those are:

    • Easily growable in large scale cultures
    • They grow well as adherent culture and in suspension, which makes them ideal for large-scale culture and GMP procedures
    • High in productivity and achieve high numbers of recombinant proteins
    • Many well-proven genetic tools, which can be used to optimize CHO cells. This reaches from gene introduction to knock-out, knock-down and post-translational silencing
    • Impressive amount of approved products 
      • (they are used for about 50 biotherapeutics, which already have been approved in the EU and USA)
    • They are adaptable for protein-free, animal-free production, serum-free culture conditions and have better stability and safety profiles
    • Many post-translational modifications can be made to reach a biosimilar, almost human-identical quality products which show exceptional biocompatibility and pharmaceutical activity

    Due to their extensive advantages CHO cells have become the most important cell line for bio research and production. Last but not least, and this may be the most important aspect of all, CHO cells have a very low virus susceptibility. In contrast to HEK cells, the risk of propagation of human viruses is significantly decreased due to their hamster origin. Therefore, production loss is mitigated and biosafety can be increased.

    CHO cells – Best choice for recombinant antibody expression

    While HEK cells have some amazing characteristics, when it comes to being on the safe side, CHO cells are definitely the way to go. With their constant progress, improvement, and tremendous advantages, such as large-scale expression in a relatively short time span, CHO cells are the obvious choice. Even more so, considering all of that can be achieved without the threat of losing time and money due to possible contaminations.

    It should have become clear by now why we at evitria only focus on CHO cells for antibody production. evitria is the leading provider for recombinant antibody production service in CHO cells and concentrates exclusively on this service. Therefore, maximum quality in a minimum of time can be guaranteed. While keeping an eye on the latest requirements, we guarantee to focus on the customer’s need to meet the particular demands of your antibody production.

    1. 1.
      Chin CL, Goh JB, Srinivasan H, et al. A human expression system based on HEK293 for the stable production of recombinant erythropoietin. Sci Rep. Published online November 14, 2019. doi:10.1038/s41598-019-53391-z
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