HLA restriction of the b3a2 specific response. (A) Clone NG-1,Hll (4.0 × 10⁴/well) T lymphocytes were incubated with 1 × 10⁵ mitomycin C–treated EBV-transformed B-lymphoblastoid cells from individuals of known HLA-DR types (see Table 2) and b2a2 or b3a2 peptides at 20 μg/mL or equivalent volume of solvent. Results are the mean ± SEM of triplicate wells. (B) DRβ1*0101 transfected L cells present b3a2 peptide NG-1 cells (5.0 × .0⁴/well) were incubated with 5 × 10⁴ mitomycin C–treated L cells transfected with either HLA-DRβ1*0101 or HLA-DRβ1*0701 and 20 μg/mL of b2a2 or b3a2 peptide. L cells alone and NG-1 (T cells) alone were also included as negative controls. Mean ± SEM of triplicate wells are shown.