Inoculation of clec9a−/− mice with F-actin resulted in increased clearance of S. aureus compared to mock-treated clec9a−/− mice (Fig. S5), indicating that Clec9a is not required for the F-actin-mediated immune responses that regulate host susceptibility to a subsequent S. aureus pneumonia. Here, CLEC9A is linked to susceptibility to pneumonia measurement.