Expi293™ Inducible Expression System Kit

The growth and expression characteristics of Expi293F cells are such that, by 7 days post-transfection, the culture medium should be close to being spent and maximal protein expression should have already been achieved. Continued incubation will result in a large decrease in cell culture viability.

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The Expi293F Inducible Cell Line was created using the same technology as the T-REx -293 Cell Line. Both cell lines have been created by stable transfection with the pcDNA 6/TR vector; thus, they ubiquitously express the tetracycline repressor (TetR) protein. The parental cell line of Expi293F Inducible cells is Expi293F Cells (Cat. No. A14527). The key differences between these 2 cell lines are:
- Expi293F Inducible cells are grown in suspension and are adapted to high-density culture (> 15x10E6 cells/mL).
- Expi293F Inducible cells grow in Expi293 Expression System and perform equivalently to parental Expi293F cells, thus making them ideal for high-yield, inducible protein expression.

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The formation of intact IgG molecules may be quantified using a sandwich ELISA designed to capture and detect rabbit IgG. Besides the rabbit IgG positive control vector, reagents, and consumables that are included in the kit, you will also need purified rabbit IgG to be used as a standard, F(ab')2-Goat anti-Rabbit IgG (H+L) Cross-Adsorbed Secondary Antibody, HRP (Cat. No. A10547), Protein A Coated Plates, Clear, 96-Well (Cat. No. 15130), TMB Substrate Kit (Cat. No. 34021), SuperBlock (TBS) Blocking Buffer (Cat. No. 37535), and PBS or TBS buffer for washes. There is an example procedure in our Protein A Coated Plates manual (https://tools.thermofisher.com/content/sfs/manuals/MAN0011310_Thermo Scientific_ProteinA_G_AG_Coat_96Well_UG.pdf). Please note that our R&D scientists determine titer values from crude cell culture supernatants using a Pall Life Sciences FortéBio Octet instrument equipped with a Protein A biosensor.

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We offer pRABBIT IgG IRES-EmGFP Positive Control Vector, Cat. No. A39243, which you can use to monitor your transfection and expression.

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Doxycycline may be used as an alternative inducing agent in the Expi293 Inducible System. It is similar to tetracycline in its mechanism of action. Doxycycline has been shown to have a longer half-life than tetracycline (48 hr vs. 24 hr, respectively). If the use of doxycycline is desired with the Expi293 Inducible System, we recommend performing a dose-response curve to determine the optimal concentration for induction.

Find additional tips, troubleshooting help, and resources within our Protein Expression Support Center.