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> Hi, all of you in the Flowing Land,
>
> We are interrested in labeling resting and activated platelets in whole blood.
> Does anybody know if there are any commercial sources of anti-CD41 MoAb
> binding only to the activated complex of gpIIb/IIIa?
> I have only found the MoAbs binding to the non-active complex produced by
> Ortho, and I know of the PAC1 clone of Dr Stanford J. Shattil. Something
> tells me I have read somewhere of the other source but cannot recall...
>
> Many thanx,
> Janek
>
> _______________________________________________________
>
> Janek Brozek e-mail: udbrozek@cyf-kr.edu.pl
>
> 2nd Dept of Internal Medicine
> Allergy and Immunology Clinic
> Jagiellonian University
> Krakow, Poland
>
>
Janek,
I believe that AMAC sold a monoclone to activated platelets for a brief,
flowing instant, then discontinued it due to difficulties in reproducably
detecting "activated" platelets with it.
This is a very interesting area, and as you may know has a few (!!)
problems. The PAC-1 antibody (an IgM isotype) binds to the gp IIbIIIa complex, and
the activation dependent epitope binds both this antibody and one or more
of the ligands which "normally" occupy it after activation. Thus, if you
activate platelets in whole blood, the PAC-1 antibody is competing with
ligands (fibrinogen) which normally occupy this binding site. Hence, if
you want to measure "activation" via this route, you will have to use
platelet enriched plasma (or purified platelets) with the disadvantage
(as well established by Ken Ault and collaborators) of dealing with
increased levels of "auto" activation. It would be very useful to have a
monoclone which detects an activation dependent epitope on gp IIb/IIIa,
IX, etc. I have seen a few reports in the literature, though I know of no
commercial source.
I am communicating this to the entire "Flow"-board in some vain hope that
commercial sources will join in the quest for these "activation"
dependent antibodies (ones which will work in whole blood- not a trivial
task). As others have stated in this forum, platelet activation has
significant clinical potential, and I would hope that as CD4/8 counts
fall from the central focus of clinical flow, other clinical uses such as
platelet activation gain more (and appropriate) attention.
A Merry Christmas to all and a Happy New (Flow and Image) Year.
Vince Shankey
Loyola University Medical Cntr.
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