Re: ionomycin and calcium flux

FACS_COPY@wehi.edu.au
Mon, 22 Jul 1996 12:40:20 +1000

frank isdell enquires:

> an investigator here has been studying the effect of various peptides on er
> negative cells (monocytes and dendritic cells).
>
> our question is whether using ionomycin (as our positive control/at various
> concentrations) should the ratio of violet to blue return to near baseline
> after the influx of calcium?
>
> we are loading with indo-1 and are using an argon ion laser tuned to UV.
> we get increases in ratio of violet to blue of about 4:1 after stimulation but
> this stays high even for 10 minutes.

In experiments run in our lab by David Tarlinton (tarlinton@wehi.edu.au)
on spleen cells, the ratio has stayed high while the ionomycin was in
the suspension (although we never tracked it as long as you have; 4
minutes tops. We presume this holds as true for your monocytes and
dendritic cells as for these lymphoid cells. The peak increase was
similar to what you've seen; 3 - 4 fold. This contrasts to the
response of the B cell component, after anti-mu stimulation, which
decays with ~50 seconds time constant.

You may or may not have noticed it yet, but the ionomycin can hang
around in the sample lines, affecting subsequent samples. We now run
the ionomycin controls last.

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