QD in submandibular lymph nodes 6 hours after injection into CSF. Confocal microscope images showing QD (red) within the subcapsular sinus of a 140 μm thick section. The region delineated by the box in (a) can be seen in (b) at higher power. The capsule of the lymph node has been stained for collagen-IV (blue) and lymph node architecture is elucidated with Sytox green nuclear stain (green). Scale = 300 μm (a), 150 μm (b).