Can I leave my Expi293F culture expressing for more than 7 days?
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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If I let my Expi293F cells grow to a higher density than recommended, will they be okay?
While the Expi293 Expression Medium can support much higher cell densities, we do not recommend growing your Expi293F cultures beyond 5-6 x 10e6 cells/mL, as subsequent transfection and protein expression efficiencies may be reduced. At higher densities, there is also the increased possibility of reaching the point of reduced culture viability. If your seed culture does exceed 5-6 x 10e6 cells/mL, passage them once or twice as detailed in the manual, monitoring them for viability and growth rate. Perform a test transfection using the Protein Expression Control IgG or an expression construct of known yield to determine if cell expression performance has been impacted.
Find additional tips, troubleshooting help, and resources within our Protein Expression Support Center.
What method do you recommend for quantifying rabbit IgG expression from pRABBIT IgG IRES-EmGFP Positive Control Vector, Cat. No. A39243?
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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Do you offer a GFP-expressing mammalian expression vector that I can use as a control to monitor my transfection and expression with the Expi systems?
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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How do I culture Expi293F GnTI-, Expi293F Inducible, or Expi293F Inducible GnTI- cells?
Expi293F GnTI-, Expi293F Inducible, and Expi293F Inducible GnTI- cell lines were derived from the parental Expi293F Cells (Cat. No. A14527) and therefore, share similar morphology and growth characteristics. They are cultured in Expi293 Expression Medium and transfected using ExpiFectamine 293 Transfection Kit following our standard Expi293 protocol.
Find additional tips, troubleshooting help, and resources within our Protein Expression Support Center.
