Flow cytometric analysis of Ag transfer from loaded DCs to B cells in vivo. (A-E) DCs purified from spleen and lymph nodes were analyzed for the expression of CD11c, MHCII, and CD317 (A). Conventional DC (CD11c^hi MHC II ⁺) were analyzed for CD8α and CD11b expression (B). Expression of CD103 gated on cDC CD8α⁺, CD11b (C) and expression of CD103 gated on cDC CD11b⁺ (D). Uptake of QDot605-coupled F(ab)′₂ anti–mouse IgG in CD11c⁺ cells (E). (F-G) DCs purified as in panel A were pulsed with 50 μg/mL of QDot655 (H-I) or 605 (E-G)–coupled F(ab)′₂ anti–mouse IgG as in Figure 6. Three or 4 C57Bl/6 mice in each recipient group were injected subcutaneously into the hind footpads with 2.5 × 10⁶ pulsed DCs. PLNs were collected after 24 hours. DCs (CD11c⁺) and B cells (CD19⁺) were analyzed by flow cytometry for the presence of QDot-F(ab)′₂ and CD103 (G), QDot-F(ab)′₂ (F,H-I). Quantifications show the total number of DCs and B cells positive for F(ab)′₂ within the collected draining PLNs.