Isotype controls at
Tue Mar 26 12:36:56 EST 1996

Think less about "concentration" and more about "content."   The best,
and probably most reliable, way to determine whether or not you have
the correct amount is to base your evauluation on the relative ug of
protein in a reagent.  If you look at the product literature, most will
indicate a range of protein / unit volume.  Controls usually contain
higher protein content since they are also usually of less demand.  Anyway,
be sure to add comparable amounts of isotype and specific antibodies to
achieve appropriate control samples.

As to the question of "how much?"...if you add less of your specific moabs
in a cocktain, then also add less isotype.  Obviously, you won't do this...
the antibodies are titred for a specific cell concentration, not suspension
volume.  Therefore, add as much of the isotype as you do the specific anti-
sera.  Staining volume is also an important issue...but that's another


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