HLA-A*0201 matched allogeneic pDCs induce highly effective tumor-specific T cell responses from HLA-A*0201+ healthy donors' PBMC in vitro.
(A,B) Autologous or allogeneic HLA-A*0201+ primary pDC sorted from the blood of healthy donors were pulsed with MelA peptide and used to stimulate HLA-A*0201+ PBMC. The specific T cell response was analyzed at d7 by tetramer labelling. (A) Percentage of MelA specific T cells (gated on CD8+ T cells). One representative experiment is shown. (B) Amplification of the absolute number of specific T cells from d0 to d7 (4 independent experiments performed with 3 different donors). (C,D) allogeneic HLA-A*0201+ PBMC from healthy donors were stimulated with the irradiated peptide-loaded HLA-A*0201+ pDC line and weekly restimulated in the presence of IL2. Specificity of the T cells was determined by tetramer labelling and flow cytometry analysis. (C) Representative dotplots gated on CD8+ T cells (left panel) and percentages (right panel) of MelA tetramer+ T cells in the culture initially and at different time points after stimulation with the pDC line loaded with MelA peptide. Flu tetramer was used as control. (D) Representative dot plots gated on CD8+ T cells (left panel) and percentages of tetramer+ CD8+ T cells obtained at days 7, 14 and 20 of the culture towards MelA (n = 18), GP100 (n = 16), TYR (n = 16) and MAGE-3 (n = 16) tumor antigens.