clairewad (asker) Apr 24, 2012:

Thank you Joanne, that was a very helpful and clear explanation

Drmanu49 Apr 19, 2012:

Thank you Joanne!

Joanne Archambault Apr 19, 2012:

Spiking of protein solutions for QC When a recombinant human protein (such as rhFVIIa) is being purified with a (bound) affinity ligand, the lab must be sure that only the protein of interest is eluted into solution, not the ligand itself. So it will run an assay (typically an ELISA) to determine how much ligand is left in the protein solution. If no ligand is found in the protein solution, you are not quite home-free yet, because something in the protein solution might be interfering with the detection of the ligand in the assay. So as a QC check, you would put your protein solution containing X mg/ml of rhFVIIa into 96-well plates and then add (aka as spiking) various amounts (increasing doses) of the affinity ligand to these wells. You then run the assay again. If you measure the same amounts of ligands as you spiked into the solution, then you can say that there are no interfering substances in the protein solution and your solution is free of any ligand.
And that it's for today's cell biology lesson...

SJLD Apr 19, 2012:

Go ahead Joanne. And perhaps explain what "doses croissantes" means too (for our general enlightenment) ;-)

clairewad (asker) Apr 19, 2012:

thanks everyone! then could someone put "spike" forward as the translation answer?

Joanne Archambault Apr 19, 2012:

Definitely use "spiked" here based on my 15 years of experience in doing such assays during my "pre-translator" career

SJLD Apr 19, 2012:

I would use "spiked" here too, and "concentrations" for "doses".