Fig 1: Forceful filariae entry results in lymphatic injury. The process of a larva entering into a lymphatic vessel resulted in various levels of lymphatic damage. a The loss of the large portion of the basement membrane (BM) and reorganization of its remnants accompanied larval entry into the collagen IV (Coll IV)-stained lymphatic collector. Left: The collecting lymphatics partially invaded by filaria. The dashed box encloses the filaria entry site magnified in the images in the right panel. Right: The damage and rearrangement of the remaining BM. Arrows point to the directional reorganization of the BM around the site of entry of the larva. b Filaria entry caused damage to both BM and the endothelial lining of the collector. The extrapolated site of entry (dashed box) of the filaria that was pictured migrating within lymphatic in the Supplementary Movie 9. Ten hours after the filaria crossed the collectors, the mouse was perfused-fixed, and the entire dorsal ear dermis was restained for collagen IV, and stained for CD31 (PECAM-1) and VE-cadherin. b (panel i) The variable presence of CD31 but not VE-cadherin (VE-cad) indicates that the remodeling of the collector took place before the fixation. Image combined from three ×100 magnification fields. b (panel ii) A 160-nm cross-section of the area dashed in bi revealed a presence of the additional chamber (arrowheads) composed of BM and the endothelial lining, suggesting a collapse of the opposing wall of the collector. c The filaria penetrated through two Lyve1-positive capillary lymphatics but did not enter their lumen. Arrowheads in 450 nm cross-sections point to the remnants of the cellular wall of the capillary lymphatic. d The image sequence of the filaria entry into lymphatic collecting vessel from Supplementary Movie 7. The green delineation (mask) was manually painted over the invaded lymphatic precollector. The inset in the top row shows the head of the larva while burrowing in the blood capillary (left) and lymphatic collecting vessel (right). Coll IV-collagen IV, VE-cad-VE-cadherin. Scale bars: a Left, 200 µm, a Right, 10 µm, b 20 µm, c 50 µm (inset 5 µm), and d 100 µm