RE: Fc-Blocking

From: Mike Clark (mrc7@mole.bio.cam.ac.uk)
Date: Fri Apr 26 2002 - 05:52:46 EST


On Mon, 15 Apr 2002 craig.turner@nbs.nhs.uk wrote:

>
> Volker,
> I'd just like to add that my experience with PBMC agrees with Randy's. However, you
> can have the odd problem with mouse IgG1 and human PBMC donors who are homozygous for
> the R131 polymorphism of Fc gamma RII (so called high-responder). mIgG1 binding can
> occur on these cells and result in an unexpected  elevated background. Statistically
> this should be about 1 in 4 but I rarely saw this many significantly high backgrounds,
> which suggest that perhaps receptor density also was an influence.
>
> Craig Turner
> Senior Scientist
> CDL
> NBS

As a follow-up to Craig's point above.

We have been looking at the binding of human IgG subclasses and mutants
thereof to transfectants of human FcgR. For the low affinity receptors we
have been using immune complexes made from whole human IgG mixed with
Fab'2 anti-light chain.

For some of these experiments we have used Goat or Donkey anti-human
reagents. Although we purchased these as Fab'2 we discovered some still
contained whole IgG.

The point we can add is that the different types and polymorphisms of
human low affinity FcR seem to show differential binding to Goat and to
Donkey antibodies. It is generally believed that Goat and Donkey IgG does
not bind human FcR but we would suggest that some caution be taken in
making this assumption.



This archive was generated by hypermail 2b29 : Sun Jan 05 2003 - 19:26:08 EST