Figure 3. Bat cells produce high levels of secreted IFN.

Cells were infected with RVFV 13 or transfected with poly IC as described before. With the help of the VSV bioassay secreted IFN was measured. Each cell line was incubated for 24 h with IFN-containing supernatants (β-propiolactone inactivated) and with pan-IFN standards diluted in medium from untreated control cells. IFN concentrations were normalized with the help of EC₅₀ values as described in the Methods section.