Figure 2: Properties of DNA/RNAs required for T cell costimulatory activity.

(a–c) Naive CD4⁺ T cells were activated with plate-bound anti-CD3∈ with various DNAs—*P<0.05, Student’s t-test (compared with anti-CD3 alone) (a); GpC with different poly tails. *P<0.05, Student’s t-test (compared with anti-CD3 alone) (b); and heat-denatured ODNs. *P<0.01, Student’s t-test (compared with the untreated control) (c). After 48 h, IL-2 production was measured by ELISA. (d) Naive CD4⁺ T cells derived from Myd88^+/− Trif^+/− and Myd88^−/− Trif^−/− mice were activated with immobilized anti-CD3∈ together with the indicated DNAs. *P<0.05, Student’s t-test (compared with anti-CD3 alone in WT cells). (e) Naive CD4⁺ T cells were stimulated with immobilized anti-CD3∈ together with all (all-PS) or partially (partial-PS) PS-modified ODN. CD4⁺ T cells were incubated with the Cy5-labelled ODN at 37 °C for 90 min, washed and analysed for incorporated ODN by flow cytometry (bottom panels). *P<0.05, Student’s t-test (compared with anti-CD3 alone). (f) Naive CD4⁺ T cells were stimulated with indicated ODNs and analysed similarly as in (e). *P<0.05, Student’s t-test (compared with anti-CD3 alone). (g) Naive CD4⁺ T cells were stimulated and analysed similarly in (c). *P<0.05, Student’s t-test (compared with the untreated control). Error bars indicate s.d. Data are representative of at least three independent experiments.