The problem I've seen when using PI and PE is that some cells will take
up not enough PI to get gated out , and these cells may look like dull
PE positives due to the small amount of PI taken up. This has shown up
in a number of situations-
1- Cells in too high a PI concentration and/or in it for too long.
2- COS cells.
Some adjustment of PI concentrations may help.
Peter Lopez
Dana Farber CAncer Institute
Plopez@sorter.dfci.harvard.edu