RE: bleed-over from doubling up?

From: Reed Doug S Dr USAMRIID (Doug.Reed@DET.AMEDD.ARMY.MIL)
Date: Tue Jan 18 2000 - 17:16:48 EST


In my opinion this would be very dangerous. T cells are not the only cells
to express CD4 or CD8 (monocytes & dendritic cells come to mind,
respectively) so you could easily see CD4 or CD8 positive cells in your
monocyte gate, which would be misleading, making you think something is
positive for something it is in fact not.

In theory it could be done IF two markers with the same fluoresence are
exclusive - i.e., if CD4 were only expressed on T cells and another marker
was only expressed on monos. In practice, this is rarely the case - NK cells
can express CD3, monos can express CD4, DC's can express CD8, T cells can
express CD11c, and so forth and so on.

And of course there are species to species variations, so that also adds
more fun to the mix.

-Doug Reed

-----Original Message-----
From: Bunny Cotleur [mailto:bcotleur@ohio.net]
Sent: Monday, January 17, 2000 7:49 AM
To: cyto-inbox
Subject: bleed-over from doubling up?



Fellow flowers-
I would like to get a consensus opinion on the following:
A Fellow I work with has been "doubling up" on stain (meaning mixing
lymphocyte markers, either CD4 or CD8 with monocyte/CD14 markers with
the SAME fluorochrome).  He feels that since you gate only on the Lymphs
or mono's, there is no cross-contamination or increase signal from the
wrong population.  Is this valid? Does anyone else do this?  Is one
fluorochrome (PE/FICT/PerCP) better than another? 
The primary reason we would like to is because we are using human cells
and barely have enough to run all the various analysis we'd like.   It
sounds a little too good....
-- 


Bunny Cotleur
Cleveland Clinic Foundation
Neurosciences NC30

216-444-1164





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