Fig. 5.

Recognition of nonhematopoietic cells by LB-PI4K2B-1S-specific CD4⁺ T cells. (A) FBs from HLA-DQB1*0603⁺ and LB-PI4K2B-1S⁺ (Upper) or HLA-DPB1*0301⁺ (Lower) individuals were seeded at 3 × 10³ cells per well and cultured for 7 days with or without 200 units/ml IFN-γ. FBs were analyzed by flow cytometry after staining with PE-labeled antibodies against HLA-DQ (filled histogram), HLA-DR (solid line), or HLA-DP (dotted line). Histograms show the MFI after culturing with (Right) or without (Left) IFN-γ. Nonstained FBs cultured with or without IFN-γ had similar MFI (data not shown). (B) (Upper) FBs from the HLA-DQB1*0603⁺ and LB-PI4K2B-1S⁺ individual treated with or without IFN-γ or patient EBV-LCLs were used as stimulator cells for CD4⁺ T cell clone ZRZ38 (5 × 10³ cells per well) in IFN-γ ELISA. (Lower) FBs from the HLA-DPB1*0301⁺ individual cultured with or without IFN-γ or HLA-DPB1*0301⁺ CLL cells were used as stimulator cells for alloreactive HLA-DPB1*0301-specific CD4⁺ T cell clone CS2–1 (5 × 10³ cells per well) in IFN-γ ELISA. The mean release of IFN-γ (ng/ml) in 50-μl supernatants of triplicate wells is shown.