Blood cells do not contribute to lymphatic endothelium at the site of vascular mixing in mice lacking PDPN, CLEC-2, or SLP-76. Vav-Cre–activated YFP expression was used to detect hematopoietic contribution to lymphatic endothelium in the intestine, the site of greatest vascular mixing in mice lacking PDPN, CLEC-2, or SLP-76. (A-D) Confocal microscopy of sections of Vav-Cre;R26RYFP neonates immunostained for the lymphatic endothelial surface protein LYVE-1 (red) and YFP (green) fails to show YFP⁺LYVE-1⁺ endothelial cells. Arrows indicate LYVE-1⁺ endothelial cells. Arrowheads indicate YFP⁺ hematopoietic cells that are frequently adjacent to but not incorporated within LYVE-1⁺ endothelium. (E-F) Analysis of Tie2-Cre;R26RYFP neonates shows numerous true LYVE-1⁺YFP⁺ endothelial cells (arrows).