IFNG and infection: Furthermore, IFN-γ levels were measured by ELISA and found to be significantly higher in Δisp2/3-infected ears at 2 wk compared with those of WT and Δisp2/3:ISP2/3 infections (Fig. 6B), which indicated an elevated Th1-type response and could explain the increased microbicidal response toward Δisp2/3 observed between 2 and 10 wk after infection.