×Aa-T cells (4 × 105 cells/well) were co-cultured with DCs (2 × 104 cells/well, pretreated with MMC) in the presence or absence of Aa (107 fixed bacteria/mL/well). In addition, anti-mouse MHC-class II Ab MAb (10 μg/mL), anti-ICOS-L MAb (10 μg/mL), a mixture of anti-CD80 MAb and anti-CD86 MAb (10 μg/mL, respectively), or control rat IgG (10μg/mL) was applied to the co-culture. Antigen-specific T cell proliferation (A) and their TNF-α production (B) were monitored following the protocol described in Figure 1. *, **, significantly lower than control cultured with Aa by Student’s t test (P < 0.05, P < 0.01, respectively).