Cross-presentation from live, not apoptotic, antigen-donor cells in vitro. DCs (5 × 104) were cultured for 16 hours with 15 × 104 live or apoptotic L OVA cells, L cells, or OVA257-264 peptide, and 1 μg/mL LPS. DCs were purified and cultured for 3 days with naive CFSE-stained OT-I CD8 T cells. At the end of the culture, cells were labeled with anti-CD8, anti-Vα2, and anti-CD44 mAb, to measure proliferation by CFSE dilution (A, mean ± SEM, representative of 3 independent experiments performed in triplicates) and activation (B, mean ± SEM, representative of 3 independent experiments performed in triplicates) by flow cytometry. (C) Cross-presentation from live, not apoptotic, antigen-donor cells in vitro. DCs were cultured with different numbers of dead cells, purified, and cultured with OT-I cells as in panels A and B, to measure the percentages of proliferating OT-I T cells (mean ± SEM, representative of 2 independent experiments performed in triplicates). **P < .01. n.d. indicates not determined.
