I've been asked to forward the following message, by a researcher, in the hope
that you can shed some light on a phenomenon we observe when staining peripheral
blood monnuclear cells with PI.
Over to you Jim ...
Message begins -
Question: why do mixed populations of white blood cells fixed in ethanol show
apparently different degrees of staining with PI ?
During experiments to examine lymphocyte apoptosis I have used peripheral blood
mononuclear cells separated on a density gradient (lymphoprep). The cells are
irradiated and kept in medium with fetal calf serum at 37C for 24 hours. They
are then fixed with 1% formaldehyde and then 70% ethanol. The samples are
stained with the TUNEL procedure (FITC) and then PI/RNase. The monocyte
population (as identified by light scatter) appears to have about 10-15%
greater red fluorescence than the lymphocytes and appears as a separate G1
peak. I wondered whether this was a recognised phenomenon, and if so why does
it occur ?
Jim Barber, Paterson Institute, Manchester
Message ends.
I will of course pass on any replies to Jim.
Thanks in advance.
Jeff Barry.