Geza Paukovics paukovic at
Sun Feb 2 23:08:16 EST 1997

Hey ho Flow-ers,

We have an established phagocytosis protocol, which HAS worked well for us.
The organism being used is Mycobacterium avium-FITC labelled (MA-FITC),
which is phagocytosed by HIV- and HIV+ monocytes. (a commercial quenching
agent is being used.) Of recent times we have switched to a Becton Dickinson
(BD) CD14-PE antobody (Ab) from a DAKO CD14-PE. The problem encountered is
that where as once I used to get staining at 37C with DAKO CD14, the BD Ab
fails to do this at the same temperature, however the BD Ab stains
beautifully at 4C. 
So the dilemma?
Has anyone come across inhibition of binding of BD Abs, (or any other Ab for
that matter) when working with MA at 37C (or any temp). Is it common for BD
Ab to become inactive if kept at 37 for only 10mins (in our protocol) with
MA or any other organism?? Does MA have properties which inactivate this
particular BD 37C?? Is there a chance of MA digesting PE at
37C, rendering it non fluorescent but still bound??
(and oh yes, the antibody hasn't expired yet) 
Fanx... In advance
Geza Paukovics - Flow Laboratory - AIDS Pathogenesis Research Unit
Macfarlane Burnet Centre                .***.  .***.           .**
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