Re: [Histonet] Re: cleaved caspase(active)

From:Cheryl Cross

Hi Carl -

Not sure I can be of any help...but one thing I've found (and one  
reason I trust Cell Signaling's ab) is that I use thymus as my  
positive control and I get nice staining in the thymic (and lymph  
node) medulla in cells that often have a shrunken, dense nucleus (ie  
look microscopically apoptotic). When I tried another antibody  
positive staining was "willy nilly" if you will - endothelial cells,  
scattered circulating leukocytes, and then many many lymphocytes  
within the thymic cortex and medulla - i just did not trust that all  
those cells were apoptotic in a healthy control!


Cheryl Cross, DVM, Dipl. ACVP
University Corporation for Atmospheric Research
College of Veterinary Medicine
University of Tennessee Department of Pathology
2407 River Drive, Room A201
Knoxville, TN 37996-4542
(423) 967-2724
fax: 865-974-5616

On Sep 10, 2007, at 3:58 PM, Carl Hobbs wrote:

> A final question, after a preamble:
> I use Cell Signalling's, Biocare's and Abcam's anti Cleaved caspase  
> 3 ( "active"   : I always add that bit in, just in case;-), on pwax  
> sections after Citric acid HIER pH6 ( no other retrieval method/nor  
> omission works, for me )
> For me, the first Ab is too variable; works very well, sometimes.
> The second works most of the time, except that  I am worried that  
> the number of positive cells makes me think that non-cleaved  
> caspase 3 is demonstrated. ( in serial sections, Biocare's Ab gave  
> nuclear positivity that was absent, repeatedly, with the other two,  
> when I judged them to be working well
> ....there appeared to be a worrying co-positivity with  
> this possible?)
> The third Ab tends to be consistent BUT , again, demonstrates less  
> cells than the Biocare Ab. As does the Cell Signalling Ab, when it  
> works.
> Final Q: Finally....has anyone actually compared the available anti  
> CC3 ( active ;-)Abs to check for fidelity????
> Any comments on these comments of mine would be gratefully recd.
> Yep..the only consistency in my comments is inconsistency!
> Curious Carl
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