Figure 3. Type I interferon does not promote Th1 commitment.

A, Purified naïve CD4⁺ T cells were stimulated with plate bound anti-CD3/anti-CD28 in the presence of IL-12 or IFN-β (1000 U/ml) as indicated in the figure. On day 7, cells were restimulated with PMA + ionomycin, and IFN-γ expression was measured by intracellular staining. B, Purified naïve CD4⁺ T cells were stimulated with IFN-α at concentrations indicated in the figure, and IFN-γ was measured by intracellular staining as describe above. C, Purified naïve CD4⁺ T cells were activated as described above for 7 days (1° conditions) where “+” indicates addition of cytokine and “−” indicates addition of neutralizing anti-cytokine antibody. These cells were then restimulated with plate-bound anti-CD3 under cytokine conditions indicated in the figure for an addition 7 days (2° conditions). Cells were then restimulated with either medium alone, or PMA + ionomycin for 1 hour. Total RNA was isolated from these cells, and IFN-γ mRNA induction was measured by qPCR. All data are referenced to the unstimulated control in condition 1.