Figure 1.

A b3a2-specific and HLA-DRB1*09:01-restricted CD4⁺ T-cell clone (SK). (a) Proliferative response of SK to graded concentrations of soluble b3a2 peptide. Autologous PBMCs were used as APCs. Proliferation was measured using the [³H]-thymidine incorporation assay. The presented values are the mean c.p.m. of duplicate cultures. (b) Inhibition of the proliferative response by anti-HLA antibodies. SK cells (5 × 10⁴) were cocultured with irradiated PBMCs (5 × 10⁵) in the presence of b3a2 peptide (0.1 μM) and indicated mAbs (10 μg/ml). (c) Proliferative response of SK cells to L-cells expressing the HLA-DR gene. SK cells (5 × 10⁴) were cocultured with irradiated L-cell transfectants (4 × 10⁴) prepulsed with the b3a2 peptide (10 μM). (d) IFN-γ secretion from SK cells (1 × 10⁵) cocultured for 24 h with THP-1 cells (5 × 10⁴) transduced with HLA-DR9 and/or BCR–ABL p210. (e) IFN-γ secretion from SK cells (5 × 10⁴) cocultured for 24 h with autologous DCs (2.5 × 10⁴) that were prepulsed with 150-Gy-irradiated THP-1 or BCR–ABL p210-transduced THP-1 cells (1 × 10⁴). (b–e) Data shown are means±s.d. of triplicate cultures and are representative of three independent triplicate experiments. (f) Expression of the genes TRAV and TRBV. (g) Representative flow cytometry profiles of TCR-Vβ22 and CD4 surface expression on SK cells. (h) TCR gene usage and V–(D)–J junction region sequences of SK. APCs, antigen-presenting cells; DCs, dendritic cells; IFN-γ, interferon-γ mAbs, monoclonal antibodies; PBMCs, peripheral blood mononuclear cells; TCR, T-cell receptor.