FIGURE 6.

Surface B7-H3 exerts a negative effect on Th1-mediated immune responses. B7-H3-expressing THP-1 cells were transfected with B7-H3-specific siRNA and co-cultured in the presence of soluble anti-CD3 and anti-CD28 antibodies (1 μg/ml of both) with CD4 memory T cells purified from healthy controls for 7 days (n = 10). A, the viability of co-cultured CD4 memory T cells was determined by the frequency of 7-aminoactinomycin D (7-AAD⁻) cells on day 3 after co-culture. B, the proliferation of CD4 memory T cells was analyzed with carboxyfluorescein succinimidyl ester (CFSE) dilution assay on day 3 after co-culture. C, on day 7, the culture supernatant was harvested, and IFN-γ and IL-17A in the supernatant were quantified using commercial ELISA kits. Each pair represents an independent experiment (n = 10). Horizontal bars and error bars show the mean ± S.E. *, p < 0.05; **, p < 0.01 by paired t test in C.