Figure 6.

WT1 derived HLA-DR.B1 peptide induced T cell responses that recognized both class I and class II peptides. (A) CD3 T cells from a donor (HLA-A*02:01⁺/A*24:02⁺) were stimulated with the DR-238 native or analog peptide five times and the peptide-specific response was measured by IFN-gamma Elispot assay against individual peptides . Each data point represents the mean +/− SD from triplicate cultures. Similarly, CD3 T cells from a donor (HLA-A*02:01^+/+) were stimulated with DR-238 native peptide (B) or DR-238 heteroclitic peptide (D) for three rounds, and the IFN-gamma secretion was measured with or without antibodies specific for the HLA-DR or its isotype control mAb (Cont mAb) (B) or HLA-ABC (D). HLA-A*02:01-restricted T cells cytotoxicity was measured against WT1⁺ leukemia cells SET-2 (C) and 697 (E) after five rounds of stimulation of the T cells. Fig. 6F Cytotoxicity of T cells stimulated five rounds from a donor who is HLA-A0201⁺ and DR.B1–15xx was measured against WT1⁺ HLA-A*02:01⁺ leukemia cells 697, SET-2, WT1⁺ HLA-A*02:01⁻ leukemia cells HL-60 and AML blasts from patients who are HLA-A*02:01⁺ or negative. Each data point represents the mean from triplicate cultures. Data represent results from seven experiments from four donors.