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. 2013 May 8;8(5):e64137. doi: 10.1371/journal.pone.0064137

Figure 4. Virus growth and IFN induction in cultured mammalian cells.

Figure 4

(A–E) Multicycle growth kinetics of wtBUNV and rBUN4KR were compared in BHK (A, D), A549 (C, E) and A549-V (B) cells by infecting triplicate wells at 0.01 PFU/cell and titrating the supernatants at the indicated time points. A–C: incubation at 37°C; D, E: incubation at 33°C. (F) Induction of IFN by treatment with poly(I∶C) or infection with rBUNdelNSs2. A549 cells were incubated at 33°C or 37°C and the supernatants assayed after 24 h. The amount of IFN produced is expressed as relative IFN units (RIU), defined as RIU  = 2N where N =  the number of two-fold dilutions of the supernatants that protected the reporter cells from EMCV challenge (see methods).