Figure 6. PDC cross-present viral antigens derived from flu-B cells to influenza-specific CD8+ T lymphocytes.

HLA-A2^neg B cells exposed (filled bars) or not (open bars) to inactivated influenza virus for 18 hours were washed and incubated with HLA-A2^pos APC (either GEN3 (A) or PDC (B)), for four hours, followed by the addition of influenza-specific CD8+ T lymphocytes (recognizing flu_58-66 influenza matrix peptide in the context of HLA-A2 molecules). After a 2-day co-culture, T cell activation was assessed by measuring the IFNγ content of the culture supernatants. In control wells, PDC were directly treated or not with the virus, or were omitted (medium). (A) Values are mean + SD of six independent experiments, except for the last control bar (SN-Flu-B cells), mean of two experiments, where Flu-B cells were washed extensively, and further incubated for 24 hours to recover the supernatant which was subsequently added to influenza-specific T cells. (B) Values are representative of two experiments and shown the mean + SD of quadruplicate wells. * P<0.05, ** P<0.005 by Student's t test.