Fc-Blocking

From: Eckstein, Volker (Volker_Eckstein@med.uni-heidelberg.de)
Date: Thu Apr 11 2002 - 06:28:10 EST


Hi flow-experts,

Fc-blocking (or not) on human PBMC prior direct or indirect staining is a
never ending discussion or story in our lab.
And the literature is confusing.
Some claim to use an IgG solution of the same origin as the used cells are.
Others an IgG solution of the same origin as the monAb (direct coupled with
fluorochromes) or the secondary polyclonal Ab are. What is the flow
community thinking about that issue and is there really a need?

Some more questions:
What is the best wash and staining buffer for human PBMC staining protocols?
Some people add BSA or HSA and some FCS in different concentrations (0.1 -
5%) to a PBS-buffer.
And what is the cell biological need to add serum components? I suppose not
blocking Fc-receptors. The explanation I've red that cells feel at home and
comfortable is unsufficient (for me).

And finally the question of speed in centrifugation of the cells for washing
after staining.
Mostly published protocols differ extremely. The range in speed starts with
200g up to 1800g or more for 1 to 10 minutes. It depends on the source of
cells that's clear but even for human PBMC there are such differences
outlined. PBMC's are hard taking cells but where is the balance between cell
loss by damage (high g) or cells loss by aspirating due to less pelleting of
the cells (low g)?

All responses are highly welcome.

Best regards

VolkerVolker Eckstein PhD
Dept. of Internal Medicine V
Medical School of the University
University of Heidelberg
GERMANY
volker_eckstein@med.uni-heidelberg.de



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