HLA-DR restriction of CD4⁺ T cells recognizing the immunodominant epitopes.

CD4⁺ T cells were propagated with pool II (A,C) or pool I (B,D). The donors and their HLA-DR types are indicated. The blank (ie, the basal level of proliferation of CD4⁺ T cells in the presence of homozygous PBMCs or LCLs as APCs) is expressed as B + PBMC or B + LCL. Alignment of overlapping sequences 111-125 and 114-127 (presented by HLA-DR1327) is reported in the box. Responses significantly higher than the blanks are indicated: **.001 < P < .05, ***P < .001 (determined by unpaired, one-tailed Student ttest).