LNDCs migrate to the medulla after influenza vaccination. (a) MP-IVM of DC arrival in the PLN periphery after UV-PR8 vaccination. Snapshots were taken at 0 and 36 min after injection and are representative of three independent surgeries (three mice) from different imaging sessions. (inset) High magnification of two individual LNDCs. (b, left) Real-time tracking of LNDCs from panel a. LNDC tracks are highlighted (white) and final destinations marked (closed circles). (right) Vector representation of complete tracks. Green and red vectors represent LNDCs with migration paths toward or away from the PLN capsule, respectively. Data are representative of three independent surgeries (three mice) from different imaging sessions. (c) Quantitation of bulk DCs from live imaging in panel a. DC spherical index (red) and surface area (black) are displayed. ANOVA (black), P < 0.005; ANOVA (red), P < 0.005. (d) Fluorescent reconstructions of in vivo–labeled CD11c-eYFP reporter PLNs. PLNs were collected at 60 min after PBS or UV-PR8 vaccination. Data are representative of three reconstructed PLNs. B, follicles; M, medulla; MM, medullary macrophage; T, T cell cortex. (e) Quantitation of the percentage of LNDCs inside or outside of the medulla as in d (n = 3 PLNs). *, P < 0.05. Mean ± SEM.