Mayra,

While it never hurts to ask, I'm not optimistic that you will find one yet.  My work with B7-H1 (PD-L1, newer nomenclature CD274) was always in frozen or non-parrafin tissue format like cell culture monolayers.  I used several clones, always unsuccessful with attempts at localization in formalin fixed paraffin.  Indeed if you survey the world literature, all others are unsuccessful.  A big urology study in 2005 looking at B7-H1 in Renal Cell Carcinoma states that patient tissue must be fresh frozen as no clones are available for archived paraffin blocks even though attempts to raise such antibodies are underway.  Many other studies over 2005-2006 to study expression in  various human neoplasms, all say same thing.  Use frozen because current antibodies don't work in paraffin.  Obviously, the immunogenically dominant epitopes of that molecule are spatial in some way and just don't stand up to any kind of fixation, processing, retrieval.  Surely someone, somewhere, sometime will make
 CD274 antibodies that work in parrafin, but if so it is an extremely recent and current development.  Good luck.

Ray Koelling
Currently Employment Challenged
Seattle, WA

-------------- Original message -------------- 
From: macantu@mdanderson.org 

> Dear Histonetters, 
> 
> This is my first time using this histosearch email. I just discovered it 
> a few weeks ago. My lab is wanting to start looking for B7-H1 (PD-L1) in 
> human tumor tissues that were fixed in paraffin. I have this working in 
> frozen tissue ( HRP detection kit from BD) but haven't been able to get it 
> to work in paraffin. And I cant find a commercially available antibody 
> that says it works in paraffin. Does anyone know of a commercially 
> available B7-H1 (PD-L1) antibody for human paraffin tissues? 
> 
> Thank you in advance, 
> 
> Mayra 
> 
> Research Assistant II 
> Dept. of Melanoma Medical Oncology 
> MD Anderson Cancer Center 
> Houston, Texas 
> Tel. 713-563-9177 
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