PTX3 interferes with the cross-presentation of vinculin epitopes to autoreactive CD8⁺ T cells upon processing of apoptotic cells. Vinculin-specific, HLA-A2-restricted CD8⁺ T cells form IFN-γ spots (number/25 000; x-axis) when challenged with the specific synthetic epitope (vinculin_823-831) or upon phagocytosis and processing of HLA-A2^- apoptotic cells expressing vinculin (apoptotic cells [AC]; A). The vinculin-specific CD8⁺ T cells forming IFN-γ spots (number/25 000; y-axis) upon phagocytosis and processing of HLA-A2^- apoptotic cells expressing vinculin were evaluated in the absence or the presence of native (▪) or denatured (□) PTX3 (μM; x-axis; B). Results are represented as mean ± SD of three independent experiments. The vinculin-specific CD8⁺ T cells forming IFN-γ spots (number/25 000; x-axis) upon phagocytosis and processing of HLA-A2^- apoptotic cells expressing vinculin by HLA-A2^- or HLA-A2⁺ DCs were evaluated. HLA-A2^- DCs also failed to activate T cells when pulsed with the specific synthetic epitope (vinculin_823-831; C). CRP (x-axis) did not influence the activation of vinculin-specific CD8⁺ T cells (IFN-γ spots number/25 000; y-axis) upon cross-presentation of apoptotic cells (D) or direct presentation of vinculin_823-831 (E). ^**P < .001, significantly different from control.