IRF3 and infection: To confirm these findings in primary MDMs, expression of IRF3, IRF5, and IRF7 was knocked down via transient transfection with pooled siRNAs (Figure 4D, Supplemental Figure 2, H–J, and Supplemental Figure 3, F–H) prior to infection with LaiΔenvGFP/G or with replication-competent Lai-YU2env virus.