UCP1, Abcam, Ab10983

UCP1 antibody from Abcam (Ab10983), used for IHC on FFPE tissue:
I have strong doubts about the specificity of this antibody. While it does stain brown fat, it also stains many other tissues, including nuclear staining in vascular endothelium, and strong cytoplasmic staining in mesothelial cells and in mammary epithelial cells. The strong staining in the mammary epithelium is retained even when diluting the antibody down to loss of staining in the brown fat (1:3000). UCP1 is supposed to be specific to brown fat, or at least it should be the tissue with the strongest expression, and that is clearly not the case with this antibody.

I have used the antibody on sections of mouse white and brown fat, at dilutions of 1:500 to 1:4000. Heat retrieval at pH6 and pH9, 1 or 2 hour incubations of the primary at room temperature, HRP-bound secondary, DAB chromogen. Dako dual enzyme block and serum-free protein block used for 15 mins each before primary incubation.