Fig 5. Entry driven by batFLUAV-HAL relies on an acidic pH.

EpoNi/22.1 cells incubated for 3 h in the absence (black bars) or presence (white bars) of ammonium chloride (50 mM) were subsequently inoculated with trypsin-treated vesicular stomatitis virus-based pseudotypes (VSVpp) harboring the indicated viral glycoproteins. At 1 h post inoculation, the inoculum was removed and the cells were further incubated for 18–20 h in the presence or absence of ammonium chloride before transduction efficiency was measured by quantification of the activity of VSVpp-encoded luciferase. For each of the different pseudotypes, transduction efficiency (given as percentage on a linear scale) was normalized against the respective control (water). The result of a single representative experiment carried out with quadruplicate samples is shown. Similar results were obtained in two independent experiments carried out with separate pseudotype preparations. Error bars indicate standard deviations. A two-tailed, unpaired student’s t-test was used to test statistical significance (* = p < 0.05).