Re: loss of fluorescence intensity

Hi Kathleen,

     This usually means the cells are a bit "sticky", and that undetected
negative cells stuck to positive ones come apart and lower purity in the
positive fraction. Since positives are easily detected, the negative sort
purity remains excellent when this happens. I would suspect some thing(s)
in the sample prep might be improved to reduce the tendency to clump before
sorting, and more rigorous "single cell" gates for sorting would solve the
problem.

     Best,

     Joe


		    Kathleen								  		    Marienfeld		 To:	 Cytometry Mailing List
<cytometry@flowcyt.cyto.purdue.edu>   
		    <kmarien@fz-b	 cc:						  		    orstel.de>		 Subject:     loss of fluorescence intensity	  		    01/29/2004								  		    06:56 AM								  



Dear Flowers,

is there any experience if  FACS-sorting leads to a loss of fluorescence
intensity especially on cells stained and pre-enriched with
FITC-labelled Ab + anti-FITC-MACS-beads prior FACS-sorting?!
(Purity of negative cells was excellent, whereas the purity of positives
was quite bad. Cells were all the time at 4°C)

any idea would be greatly appreciate....
:-)
Kathleen








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