MDDCs transfer EV71 to susceptible cells. (A) MDDC-mediated EV71 transmission. MDDCs were incubated with different amounts of EV71 for 1 h at 37°C, after washing, EV71-loaded MDDCs were cocultured or not (DC alone) with RD cells for 1 day. Viral replication was detected by quantifying viral mRNA level. One representative from three donors or repeats with similar results is shown. (B) Separation of MDDCs with RD cells abolished EV71 transfer. EV71-loaded MDDCs were separated from RD cells by Transwell insert, and viral transmission was detected as above. (C, D) Replication of transferred-EV71 killed RD target cells. PI-exclusion staining was used to examine cell death during coculture, and MDDCs (CD11c+) and RD cells (CD11c−) were distinguished by CD11c staining (C), and cell death was observed under light microscopy (D). Data are mean ± SD. ***P <0.001 and *P <0.05 were considered significant differences in paired t test.