Fig. 1.

Absence of CD31 favors DC migration to the draining lymph nodes. DC migration to the lymph nodes was evaluated with the FITC-painting assay in CD31^+/+ mice and CD31^−/− littermates (n = 6 mice per group). (A) Absolute numbers of leukocytes (CD45⁺) and DCs (CD45⁺CD11c⁺) in lymph nodes were similar in CD31^+/+ and CD31^−/− mice at steady state. (B) Representative contour plots show how the recent skin-derived and activated DCs were identified (FITC⁺CD80⁺) in the lymph nodes of CD31^+/+ and CD31^−/− mice. (C) Number of FITC⁺ DCs in the draining lymph nodes of the CD31^+/+ mice was significantly lower than that in the CD31^−/− mice. *P < 0.05 vs. CD31^+/+. (D) Gating strategy used to identify DC subsets in the lymph nodes: DCs (MHCII⁺CD11c⁺ cells) were identified as plasmacytoid by the expression of B220 [B220⁺, plasmacytoid DCs (pDCs)]; CD11b⁺B220⁻ cells were further subdivided into CD103⁺ and CD103⁻ myeloid DCs, and the remaining CD11b^low (lymphoid) DCs were classified as CD4⁺ or CD8⁺ single-positive DCs and CD4⁻CD8⁻ double-negative DCs. (E) Absolute number of the DC subsets described in D among FITC⁺ DCs. The analysis shows that FITC painting induces the recruitment of myeloid CD103⁻ and CD4⁻CD8⁻ double-negative lymphoid DCs in the draining lymph node. The absence of CD31 was associated with a generalized increase in FITC⁺ DCs, regardless of their subset. *P < 0.05 vs. CD31^+/+.