Figure 3. Transporter Activity Is Required in Either the Apoptotic Cell or the DC for Efficient Cross-Presentation of Antigen.

RMA/S cells were infected with influenza and irradiated with UVB to allow for antigen loading and the induction of apoptotic death. Co-cultures were generated as described in the Materials and Methods using WT DCs (A) or TAP^−/− DCs (B). DCs were harvested and tested for their ability to cross-present antigen and activate influenza-reactive CD8⁺ T cells as measured in a 40-h ELISPOT assay. To evaluate loading of MHC II, WT DCs and TAP^−/−DCs that had captured apoptotic antigen were tested for their ability to activate influenza-reactive CD4+ T cells. Data are representative of four experiments. Values are averages of triplicate wells with error bars indicating standard deviation.