t-PA is localized in WP bodies in endothelial cells from human skeletal muscle.

Skeletal muscle fragments were thin sectioned and labeled with anti–t-PA monoclonal antibodies and immunogold. t-PA antigen was identified in the arteriolar endothelial cells, and found in many typical elongated and striated WP bodies (4 panels are shown). Original magnification: × 74 000 (panels A-D).