Re: Phagocytosis by Flow

From: John Waitumbi (waitumbi@net2000ke.com)
Date: Sat May 22 1999 - 13:39:40 EST


Koratich,

In reply to your question on phagocytosis by flow, you could probably
modify the following protocol which I learnt in a flow cytometry course at
Sheffield:

	1. Use siliconised glass tubes
	2. Add 40 ul of a 2.5% suspension of fluorescent 1 um diameter
microspheres (Polysciences) 	to the macrophages suspended in 1.9 mls PBS.
Incubate at 37 C for 60 min.
	3. Gently pipette the suspension onto 1 ml fetal calf serum and centrifuge
to generate a cell 	pellet (200g)
	4. Aspirate the supernatant containing free beads and discard
	5. Resuspend the cells in 1-2 mls PBS+0.1% trypsin (type IIIs, Sigma) and
5nMol EDTA (ie 	equal parts stock tissue culture Trypsin/Versine). Incubate
at 37C for 10 min to detach 	adherent but non phagocytosed beads
	6. Repeat step 3.
	7. Wash cells X2 in cold PBS
	8. Analyse by flow

John 

------------------------------------------------------------------------
Dr. John N. Waitumbi
c/o Dr  Jose A. Stoute, 
USAMRU, Unit 64109, Box 401
APO AE 09831-4109
Kenya
Phone +254 35 22942
Email:waitumbi@net2000ke.com
Fax +254 35 22903


> Hi all,
> 
> Does anyone have a good protocol for doing phagocytic activity of
peritoneal
> macrophages using FITC beads by flow.  We are currently harvesting the
> macrophages by lavage and adherence to 6-well TC plates for 2 hours in
DMEM
> w/o serum.  We then wash and add DMEM w/ 10% FBS at let them incubate ON.
> We then wash and add  1E8 beads, which is roughly a 100:1 bead to cell
> ratio.  This is incubated for 90 mins. and then washed to remove most of
the
> free beads.  This all works fairly well and the cells look good under the
> scope.  Our problem is how to get the cells to detach so we can run them
on
> the flow without causing disruption of the membrane and loss of beads. 
We
> are currently using 0.4% EDTA with poor results.  We have found a
protocol
> that uses dispase and will try that next.  Any ideas on other things to
try
> would be appreciated.  Further, any suggestions on the method in general
are
> also welcome.
> 
> TIA,
> 
> Mike Koratich
> Cell Biology and Immunology Group
> Serquest
> Southern Research Institute
> Birmingham AL 35205



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