Imaging of pulmonary lymphatics in LPS-treated PF4-Cre:Rosa26 ^mTmG mice and Prox1-eGFP mice given PKH26-PCL to label alveolar macrophages. (A) Intravital images of an LPS-treated PF4-Cre:Rosa26^mTmG mouse showing platelets in blood vessels and recombined cells in bronchovascular cuff spaces but only very rare recombined cells and possible platelets in the lymph. (B and C) C57BL/6 mice were given PKH26-PCL or vehicle control o.a., and 5 days later, BAL cells were isolated for measurement of efficiency of labeling of alveolar macrophages with PKH26, quantified in C. (D)Prox1-eGFP mice were given PKH26-PCL o.a. to label alveolar macrophages, then 5 days later were given LPS via the o.a. route. Intravital imaging at 24 h after LPS treatment showed labeling of alveolar macrophages (alv. macs, asterisks) in alveoli but not in lymphatic vessels. The P value in C is from an unpaired, two-tailed t test, group sizes: (A) n = 3; (B–D) n = 5.