[David Hacker]

Hello,

I am returning to Nick’s question about LIF expression and endotoxin contamination. We have expressed mLIF as an Fc fusion protein in HEK293 cells. The protein is functional as a fusion protein so that there is no need to remove the Fc domain. We used a human IgG1 Fc domain.

For endotoxin screening we have been using the HEK-Blue-mTLR4 cells from Invitrogen as an assay system. The assay is economically interesting when you have many samples to test, but it is labor intensive if you are only measuring 1-2 samples at a time. We are in the process of buying the Charles River nexgen PTS system (about 7’000 euros). This is a good system if you only occasionally need to test a sample as you just have a single-use assay cartridge for each sample and the assay takes 15 minutes with no set-up time. The assay cartridge costs about 50 euros and thus not very economic if you have many samples per week.

David Hacker
Protein Production and Structure Core Facility
EPFL

[Jean-Philippe Gaudry]

Hello David,

Thank you for your comment. A little precision: the HEK-Blue-mTLR4 cells is from Invivogen (not Invitrogen).

Best regards,

Jean-Philippe

[Author]

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