rVV infection blocks DC maturation, while mature DCs infected by rVV maintain a mature phenotype. An rVV coding for GFP was used to infect DCs for 8 hours. rVV-infected immature DCs were mock treated (A) or exposed to LPS for 8 hours (B). Cells were then analyzed by fluorescence-activated cell sorting (FACS) for expression of GFP, I-A^k, and CD86 and for IL-12 production. Mock-infected cells exposed to LPS (C) were analyzed as controls. To overcome rVV interference with DC maturation, DCs were first matured for 8 hours with LPS, then infected with rVV-GFP (D) and analyzed to determine infection efficiency and level of activation. The average expression of I-A^k (E) and CD86 (F) in the different samples are shown (average of 3 experiments).