Resident CD8(+) and migratory CD103(+) dendritic cells control CD8 T cell immunity during acute influenza infection

The identification of the specific DC subsets providing a critical role in presenting influenza antigens to naïve T cell precursors remains contentious and under considerable debate. Here we show that CD8(+) T lymphocyte (TCD8+) responses are severely hampered in C57BL/6 mice deficient in the transcription factor Batf3 after intranasal challenge with influenza A virus (IAV). This transcription factor is required for the development of lymph node resident CD8(+) and migratory CD103(+)CD11b(-) DCs and we found both of these subtypes could efficiently stimulate anti-IAV TCD8+. Using a similar ex vivo approach, many publications on this subject matter excluded a role for resident, non-migratory CD8(+) DC. We postulate the differences reported can partially be explained by how DC are phenotyped, namely the use of MHC class II to segregate subtypes. Our results show that resident CD8(+) DC upregulate this marker during IAV infection and we advise against its use when isolating DC subtypes.