zinc formalin fixation or zinc fixative?

<< Previous Message | Next Message >>
From:Gayle Callis <uvsgc@msu.oscs.montana.edu> (by way of histonet)
Content-Type:text/plain; charset="us-ascii"

A comment about zinc formalin fixation for these murine cell surface
markers.  Andi is correct about the fact the these, particularly the CD4
and CD8 markers may  not stain after FFPE prepared tissues.


Pharmingen does not tout zinc formalin fixed tissue, they recommend
(in their catalog with recipe and how to fix) a zinc fixative which does
NOT contain formalin. It is TRIS buffered Zinc fixative, containing zinc
chloride, zinc acetate and calcium acetate.  I think their use of the
terminology Zinc Fixative is easily confused with zinc formalin which we
are so familiar with.  Kind of wish they would call it ZincTRIS or
at least nonformalin zinc fixative, sorry just my hangup, but far less
confusing.  This fixative will work with these cell marker antibodies,
per publication by Nitta et al, in Cell Vision 1:73, 1997. Alk phos substrate
method must be used, as you cannot rid tissue of endogenous peroxidase after
the ZincTris fixation.  This fixative also eliminates the need for
antigen retrieval IF you make sure the tissue is 100% ZnTris fixed,
the alcohols in processing continue the fixation, and
I am aware of one person who had to retrieve because of this reason.
Somewhat defeated one  purpose of this nice fixative!

PharMingen does give a NBF fixative, and maybe zinc formalin would work,
with extensive antigen retrieval, but it has not worked for many others with
these CD markers. I was hoping to point out their recommendation of this
formalin free zinc fixative and alleviate confusion before one launches
into a huge mouse tissue  project with the wrong fixative.

Some other things learned about ZnTris fixative, is some tissues make take
less time to fix, others longer than publication recommendation, so a
fixation time study might be in order to optimize fixation first.

Sorry to be a Bah, Humbug, but hope this helps avoid confusion.
We prefer to do frozens, acetone fixed but have had success with ZnTris,
formalin of any kind is avoided for murine CD markers

I would like to know if anyone has ever had good success with formalin based
fixatives with murine CD3, 4, and 8.

What a long lecture!
Gayle Callis


Hi Luis
Among others, Pharmingen (http://www.pharmingen.com/) offers rat monoclonals
against mouse CD3,4,8. Be aware that most of these mAbs are not suitable for
FFPE tissues. You will have to work on fresh frozen tissues, or in some
instances on zinc-formalin fixed material. Good luck!
Andi Kappeler
Institute of Pathology, University of Bern

<< Previous Message | Next Message >>