The relative efficiency of acquisition of MHC: peptide complexes and cross-presentation depends on dendritic cell type

LA Smyth, N Harker, W Turnbull… - The Journal of …, 2008 - journals.aai.org
LA Smyth, N Harker, W Turnbull, H El-Doueik, L Klavinskis, D Kioussis, G Lombardi
The Journal of Immunology, 2008journals.aai.org
Intercellular exchange of MHC molecules has been reported between many cells, including
professional and nonprofessional APCs. This phenomenon may contribute to T cell
immunity to pathogens. In this study, we addressed whether the transfer of MHC class I:
peptide complexes between cells plays a role in T cell responses and compare this to
conventional cross-presentation. We observed that dsRNA-matured bone marrow-derived
dendritic cells (BMDCs) acquired peptide: MHC complexes from other BMDCs either pulsed …
Abstract
Intercellular exchange of MHC molecules has been reported between many cells, including professional and nonprofessional APCs. This phenomenon may contribute to T cell immunity to pathogens. In this study, we addressed whether the transfer of MHC class I: peptide complexes between cells plays a role in T cell responses and compare this to conventional cross-presentation. We observed that dsRNA-matured bone marrow-derived dendritic cells (BMDCs) acquired peptide: MHC complexes from other BMDCs either pulsed with OVA 257–264 peptide, soluble OVA, or infected with a recombinant adenovirus expressing OVA. In addition, BMDCs were capable of acquiring MHC: peptide complexes from epithelial cells. Spleen-derived CD8α+ and CD8α− dendritic cells (DCs) also acquired MHC: peptide complexes from BMDCs pulsed with OVA 257–264 peptide. However, the efficiency of acquisition by these ex vivo derived DCs is much lower than acquisition by BMDC. In all cases, the acquired MHC: peptide complexes were functional in that they induced Ag-specific CD8+ T cell proliferation. The efficiency of MHC transfer was compared with cross-presentation for splenic CD8α+ and CD8α− as well as BMDCs. CD8α+ DCs were more efficient at inducing T cell proliferation when they acquired Ag via cross-presentation, the opposite was observed for BMDCs and splenic CD8α− DCs. We conclude from these observations that the relative efficiency of MHC transfer vs cross-presentation differs markedly between different DC subsets.
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