Immunohistologic analysis of endothelial TNF expression.

(A) TNF staining on the endothelial lining (arrow) of the tumor-associated vasculature of transplanted meth A sarcomas. A strong autofluorescent reaction of some trapped red blood cells is also visible. (B) Weak staining of blood vessels (arrow) for TNF can be observed in paraffin-embedded dermal tissue distant from the tumor. (C,D) Double staining of tmTNF and CD31 as an endothelial cell marker in frozen sections of transplanted meth A sarcomas using a TNFR2-IgG fusion protein (C) and a rat antimouse CD31-specific mAb (D).