Actin cytoskeletal reorganization and ion channels are necessary for uptake and presentation of antigen from apoptotic and necrotic cells. Immature HLA A^*0201⁺ DCs were preincubated with increasing doses of CCD or DMA. Pretreated DCs were thereafter cocultured at a 1:2 ratio with HLA-mismatched apoptotic or necrotic monocytes expressing MP and the same dose of inhibitor for 10 to 12 hours. DCs pulsed with 100 nM MP peptide were used as controls. All groups of CCD-treated (A) or DMA-treated (B) DCs were fixed with glutaraldehyde cocultured with Flu16; responses were monitored by IFN-γ ELISPOT assay. The left axis shows cross-presentation and the right peptide presentation. Controls consisting of dead cells and Flu16 alone or together did not induce any IFN-γ production (unpublished data). One representative experiment of 4 is shown.