Increased lymphangiogenesis in LTβ^−/− mouse skin after induction of inflammation. (A) Fluorescence microscopy of the site of immunization with ovalbumin and CFA after injection of FITC-conjugated nanoparticles reveals more prominent and extensive lymphatic vessel networks near immunization sites in LTβ^−/− mice compared with LTα^−/− and WT mice. Pale green at day 0 represents autofluorescence. Black blood vessels are apparent and even more obvious after immunization. Lymphatic vessels are bright green (6.5× objective). (B) More peri-immunization depot sites showed uptake of the nanoparticles by lymphatics in LTβ^−/− than WT and LTα^−/− mice (n = 3 per group with total of 6 depot regions per group).