FIG 1.

In vitro passage of PIV5-based RSV vaccine constructs. (A) Schematic of PIV5-vectored RSV vaccine constructs. NP, nucleoprotein; V, V protein; P, phosphoprotein; M, matrix protein; F, fusion protein; SH, small hydrophobic protein; HN, hemagglutinin-neuraminidase protein; L, RNA-dependent RNA polymerase; RSV F, respiratory syncytial virus fusion protein; RSV G, respiratory syncytial virus G attachment protein. (B) Vero cells were infected with PIV5-RSV-F (HN-L), PIV5-RSV-G (HN-L), PIV5-RSV-F (SH-HN), or PIV5ΔSH-RSV-F at an MOI of 1 PFU per cell (high MOI) or 0.01 PFU per cell (low MOI). For high-MOI-passage conditions, 500 μl of infected cell culture supernatant was used to infect fresh Vero cells every 4 to 5 days, for a total of 11 passages. For low-MOI-passage conditions, the cell culture supernatant was diluted 1:10,000 and 2.5 ml was used for infection of fresh Vero cells.