Mice lacking type I IFNs are partially rescued from c-di-AMP-mediated immune inhibition.

<p><b>A</b>. B6 or <i>IFNAR1^−/−</i> mice were immunized with 10³ CFU ActA⁻Lm-OVA (Δ<i>actA</i>) in the presence (open triangles) or absence (open circles) of 100 µg c-di-AMP or <b>B</b>. <i>tetR</i>ActA⁻Lm-OVA (<i>tetR</i>Δ<i>actA</i>) (open triangles). Naïve mice were administered PBS (closed circles). Mice were challenged 30–38 days later with 2×10⁵ CFU WT Lm-OVA and 3 days post challenge, CFU were enumerated from spleens. The dashed line represents limit of detection. Data are presented as the cumulative results from 3 independent experiments (ns = not significant, *p<0.05, **p<0.005, ***p<0.0005).