Fig. 2.

Priming of CD4 T cells and IgE responses initiated by alum are reduced in STING^−/− mice, and these effects are independent of type I IFNs. (A) STING^−/− or WT littermate control mice were immunized with 10 μg of 3K-ova + 200 μg of Alhydrogel in the calf muscle. Before injection, the antigen/adjuvant was mixed with either 5 mg of BSA or DNase I. Popliteal LNs were harvested 7 d after immunization and stained with tetramers and Abs as described in Materials and Methods. Bars on the graph show the mean total number of 3K/IA^b tetramer-positive CD44^hi CD4 T cells per mouse. Data are combined from two experiments (n = 6 mice per group). (B) STING^−/− or WT littermate control mice were immunized with 10 μg of ova (Ova) + alum. Sera were tested for the presence of ova-specific Abs 14 d later. RU, relative units. (C) STING^−/− mice were primed and boosted with 10 μg of ova (Ova) + 200 μg of alum, and ova-specific IgE Abs in the sera were analyzed 7 d after the boost by ELISA. Ab data are combined from two separate experiments. Lines on the graphs indicate means, and the error bars indicate SEM. (D) B6 WT mice and IFNAR^−/− mice were injected with 10 μg of 3K-ova and 200 μg of Alhydrogel in the calf muscle and compared with naive controls (open bars). Before injection, the antigen/adjuvant was mixed with either 5 mg of BSA (black bars) or DNase I (gray bars). Popliteal LNs were harvested 7 d after immunization and stained with tetramers and Abs as described in Materials and Methods. Bars on graphs show the mean total number of 3K/IA^b tetramer-positive CD44^hi CD4 T cells per mouse. Data are from a single representative of two experiments (n = 4 mice per group). Statistical differences in A and D were determined using one-way ANOVA with a Bonferroni posttest. Statistical differences in B and C were determined using an unpaired t test. *P < 0.05; **P < 0.01; ***P < 0.001; not significant (ns) indicates P > 0.05 for select comparisons.