Analysis of the EGFP expression in YF 17D virus-infected Vero cells. (A) Flow citometry analysis at 72 h – post infection. Dot plots show the expression of YF antigens detected by intracellular staining with murine hyperimmune serum against YF virus (α-YF; y-axis) and of EGFP by direct detection of its fluorescence (EGFP; x-axis). The controls consisted of cells infected with no virus (control) and the parental virus (YF17D/E200T3). Cells infected by the recombinant virus were labeled (EGFP- α-YF) or (EGFP) only. The percentages of gated cell populations are indicated in each plot. (B) Immunoprecipitation profiles of protein extracts from supernatant and infected Vero cells with either YF 17DD or YF 17D/Esa/5.1glic viruses. These samples were immunoprecipitated with murine hyperimmune serum against yellow fever virus (α-YF) or rabbit polyclonal antiserum directed to EGFP (α-EGFP). Molecular weight markers are indicated on the left side of the figure whereas viral and recombinant proteins are identified on the right side.