RE: Dead cells and sorting

From: Moss, Delynn M. (dmm3@CDC.GOV)
Date: Thu Sep 19 2002 - 14:26:10 EST


Todd,

Would using propidium iodide (PI) help?  We use PI to eliminate dead cells
from monodispersed preparations from mouse spleens when we separate B-cells
for hybridoma preparations.  All dead cells will take up the PI and yield
high fluoresecence in the FL3 detector if you are using 488 excitation.
Thus, you can gate the dead cells out.	I will give you more specifics, if
you are interested.

Delynn Moss
Division of Parasitic Diseases
CDC

-----Original Message-----
From: Todd Belanger [mailto:tbelanger@vaccinex.com]
Sent: Wednesday, September 18, 2002 11:04 PM
To: cyto-inbox
Subject: Dead cells and sorting

Hi fellow sorters:

I am starting to sort samples that are infected with a viral vector that
tends to kill the fells over time. as a result when the samples arrive for
me to sort there are as many as 20-50% dead cells in the sample. The
staining/prep of the cells is a lengthy process and does contribute to the
lack of health of the samples. Adding a lengthy process to remove dead cells
after the samples have been stained may not be feasible due to the time
required to prepare the cells in the first place. I know that this is not
good for the sort and would like some advice as to what to do. I haven't had
to deal with such death in any of my other sorts and have had good luck with
those with decent yields and purities. Now, with the dead cells included in
the samples my purities are awful ( it almost looks like I didn't sort teh
sample!). I am running a Vantage w/ Diva using the same settings (using
Accudrop) I used to sort cells that are not infected with a virus and with
similar percentages of positive events in the samples. The samples with no
virus only had 5-10% dead cells at most. Samples are filtered before
sorting.

How does the dead cells and debris in the sample effect the sort?

Any suggestions on how to easily clean up the samples? All suggestions and
help are appreciated.

Thanks again,
Todd

Todd J. Belanger
Cellualr Immunology
Vaccinex, Inc.



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