MORPHOLOGICAL CHANGE IN TUMOR ENDOTHELIAL-CELLS INDUCED BY NATURAL-TYPE HUMAN TUMOR-NECROSIS-FACTOR

The effects of natural-type human tumor necrosis factor (nh-TNF) on tu mor endothelial cells of experimental brain tumors were investigated e lectron microscopically. Tumor vessels with hypertrophic endothelial c ells were observed 12 and 24 hr after an intralesional administration of 5,000 U of nh-TNF. Increased biosynthetic organelles such as the Go lgi complex and rough endoplasmic reticulum were evident in the plump cytoplasms. These endothelial cells resembled those in high endothelia l venules (HEV) functionally characterized by the high permeability of leukocytes. In addition, close interactions between these endothelial cells and leukocytes were observed. Our findings indicated that nh-TN F could promote the morphological change in tumor endothelial cells in to HEV-like cells.