Fig. 6.

Mutant MHC II reduces binding of conformational antibody and T cell stimulating ability. CHO cells were transfected with wild-type A^k or mutant A^k (represented as A^k and mutant-A^k, respectively). A: The binding of mAb 11-5.2 (conformational antibody) to A^k and mutant-A^k was to assess cell surface expression of the Ia.2 epitope (shaded box). The cells were stained with FITC-conjugated mAb 11-5.2. The binding of mAb 10-3.6 (nonconformational antibody) to A^k and mutant-A^k was to assess total cell surface expression of A^k (open box). The cells were stained with PE-conjugated mAb 10-3.6. The binding was expressed in terms of relative MFI with respect to A^k. MFI of A^k transfected cells were considered as 1,000. B: The anti-HEL T cell hybridomas (HyH12.6) were cocultured with A^k and mutant-A^k in the presence of HEL_46-61 peptide (100 μM). The resulting IL-2 productions in the supernatant were measured by ELISA. ***P < 0.0005 with respect to N-MΦs.