RE: controlling autofluorescence red cells/whole blood

From: Olindo Assis Martins Filho (oamfilho@cpqrr.fiocruz.br)
Date: Thu Feb 10 2000 - 10:10:58 EST


Hi Steve,

I have worked for a long time with whole blood and I never noticed 
autofluorescence interference unless in a few situations. Samples already 
labeled for over 2-3 days, cultured monocytes, eosinophils are always 
autoflurescent, CD8+ cells from some HIV+ patients and problems with the 
quality of my Fetal Bovine serum in experiments that use it as a 
macromolecular media.

As far as erithocytes I only found autofluorescence when I fixed them 
before the procedure, using either PFA or GA (glutaraldehyde).

If you can give more details about your protocol I will be happy to help 
you. I have worked with red blood cells with different protocols with no 
problem. Moreover, I have tested human as well as dog RBC.

I am looking foward to hear from you,

best regards,

Olindo

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De: 	Steve Woodard[SMTP:steve.woodard@ibb.gatech.edu]
Enviada: 	Terca-feira, 8 de Fevereiro de 2000 18:06
Para: 	Cytometry Mailing List
Assunto: 	controlling autofluorescence red cells/whole blood


Does anyone have experience in performing analysis of red cells in whole
blood. I am encountering problems with the amount of autofluorescence
associated with whole blood samples. When I look at FL1 VS FL2  plots of
"Cells Only",  the majority of cells are in the lower left quadrant. There
are some cells that are found at a 45 degree angle to the lower left
quadrant. It reminds me of a "comet". The problem is that the
autofluorescence is interfering with stained cells that are double
positives.  In order to complicate matters, we are looking for 50 events
out of 50,000 in the whole blood ( 0.1%). How is this type of problem
usually solved ? I tried using trypan blue but there was only a minor
reduction in autofluorescence. I came across crystal violet as a quencher
but fixation of the whole blood is not an option.

thanks in advance for your responses,

Steve



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