Characterization of the CD4⁺ T-cell response to MAGE-3_171-185.

CD4⁺ T cells from donor/patient 5 (HLA-DR4, HLA-DR11) were propagated by weekly restimulation with pool I. (A-B) Proliferative responses, measured in 2-day microproliferation assays, to each single peptide forming pool I (10 μg/mL) after 3 weeks (A) and after 12 weeks (B) of propagation of the line. The blank (ie, the basal level of proliferation of CD4⁺ T cells in the presence of homozygous PBMCs as APCs) is expressed as B + DR11-PBMC or B + DR4-PBMC or B + DR4-LCL. (C) IFN-γ release of CD4⁺ T cells in the presence of melanoma cells, DR4-LCL, MAGE-3_171-185–pulsed DR4-LCL, DR4-LCL-M3, and DR4-LCL-IiM3. The data shown in panels A to C are means of triplicate determinations ± SDs. Responses significantly higher than the blanks are indicated: *P < .05, **.001 < P < .05, ***P < .001 (determined by unpaired, one-tailed Student t test).