Fig. 3.

Cytokine secretion profile of CD8+ T cells derived from WT C57BL/6 or ERAP1-deficient mice. C56BL/6 mice (n = 8) or ERAP1^−/− mice (n = 8) were immunized I.M. in the tibialis anterior with viral particles of Ad5-C. difficile-TA (1×10¹⁰). At day 21, mice were sacrificed and splenocytes were harvested and stimulated for 6h at 37°C with a pool of peptides that responded in the WT mice only, the WT IDTAPs as described in Methods, (A and B), with a pool of peptides that responded in the ERAP1^−/− mice only, the ERAP1^−/− IDTAPs as described in Methods (C and D). (A) Representative example of IFN-γ-, TNF-α- or IFN-γ/TNF-α-producing splenic CD8+ T cells stimulated with the WT IDTAPs. (C) Representative example of IFN-γ-, TNF-α- or IFN-γ/TNF-α-producing splenic CD8+ T cells stimulated with the ERAP1^−/− IDTAPs. Gates were set based on negative control (naIve) and placed consistently across samples. (B) The total frequency of splenic CD8+ T cells expressing IFN-γ, TNF-α or IFN-γ/TNF-α stimulated with the WT IDTAPs. (D) The total frequency of splenic CD8+ T cells expressing IFN-γ, TNF-α or IFN-γ/TNF-α stimulated with the ERAP1^−/− IDTAPs. The bars represent means ± SEM. Statistical analysis was completed using one-way ANOVA with a Student–Newman–Keuls post hoc test. A P value < 0.05 was statistically significant. ***P < 0.001, statistically significant from the other three groups of animals. **P < 0.01, statistically significant from the other groups of animals.