Cross-presentation is dependent on peptide loading and transport of newly synthesized MHC class I from the ER. Immature HLA A^*0201⁺ DCs were cocultured for about 6 hours with apoptotic or necrotic monocytes expressing MP, or MP peptide and a maturation stimulus. Brefeldin A was added at increasing concentrations to the DCs. The ratio of dead cells to DCs was 2:1 and MP peptide concentration 100 nM. All groups of DCs were fixed by glutaraldehyde and cocultured with Flu16 and responses assessed by IFN-γ ELISPOT assay. The DC/T cell ratio was 4:1. One representative experiment of 4 is shown.