In vivo migration of mature and immature DCs into skin during a contact hypersensitivity reaction in comparison to sensitized T cells.

Balb/c bone marrow–derived DCs, freshly isolated T cells from oxazolone-sensitized Balb/c donors, or the mouse DC line XS52 were labeled with ⁵¹Cr and injected into the tail vein of sensitized and challenged Balb/c recipients. After 6 hours mice were killed and the accumulation of radioactivity in the oxazolone-challenged inflamed ear (hatched bars, +) was measured by γ counting and compared to the vehicle-treated control ear (black bars, −). The y-axis (percent of cpm) refers to radioactivity in the ear with respect to radioactivity of all harvested organs set as 100%. (A) Immature DCs cultured for 5 days, mature DCs cultured for 11 days without LPS (mature DC) or with LPS for the last 24 hours (mature DC, LPS activated), immature DCs fixed in PFA (immature DC, PFA fixed), and the immature DC line XS52 were compared. The means and SDs for each value were calculated from 3 independent animals. Immigration of DCs was statistically significant for immature DCs and XS52, respectively (P < .001), but not for mature DCs. (B) Bulk cultures of immature DCs were not depleted for Lin⁺ cells, whereas Lin⁻ cultures were immature DCs generated from bone marrow cells that had been depleted for CD3⁺, B220⁺, Gr1⁺, and MHC-II⁺ cells at the beginning of the culture period. Lin⁻ DCs and undepleted DCs were cultured for 5 days and injected intravenously as above. (C) Accumulation of immature DCs (left panel) or T cells (right panel) 6 hours and 48 hours after tail vein injection. For the 48-hour time points, ears of recipient mice were treated twice at 6 and at 24 hours after cell injection with a steroid cream to resolve inflammation due to the allergic contact dermatitis. The values represent groups of at least 3 mice each.