Fig. 4.

Cells transfected with SFV RNA devoid of capsid release infectious material. a The indicated cell lines were electroporated with SFV-enh-spike RNA as described in “Materials and methods”, supernatants were collected at 24 h and titrated by infecting BHK cell monolayers that were analysed by IF with α-spike serum. b Propagation of infectious material released by SFV-enh-spike-transfected HuH-7 cells was assessed by infecting BHK cells monolayers at MOI 0.05 and analysing spike expression at the indicated times by IF (magnification: ×100; scale bars 50 μm). c Effect of different agents on the infectivity of infectious microvesicles (iMVs) or wtSFV used as control (MOI 0.1 in both cases). For NH₄Cl treatment, cells were incubated with this agent at a concentration of 20 mM during the 60 min. virus adsorption period (ad), during adsorption and a 4-h post-infection period (ad + inf), or only during the 4 h post-infection period (inf). The percentage of infectivity in each case was calculated considering the infectivity of non-treated samples as 100 % (non-treat). Prot K, proteinase K; Trit. X100, Triton X-100. In a and c data are the mean + SD of three experiments. ***p < 0.001