Antigen delivery to early endosomes eliminates the superiority of human blood BDCA3+ dendritic cells at cross presentation

L Cohn, B Chatterjee, F Esselborn… - Journal of Experimental …, 2013 - rupress.org
L Cohn, B Chatterjee, F Esselborn, A Smed-Sörensen, N Nakamura, C Chalouni, BC Lee…
Journal of Experimental Medicine, 2013rupress.org
Human BDCA3+ dendritic cells (DCs), the proposed equivalent to mouse CD8α+ DCs, are
widely thought to cross present antigens on MHC class I (MHCI) molecules more efficiently
than other DC populations. If true, it is unclear whether this reflects specialization for cross
presentation or a generally enhanced ability to present antigens on MHCI. We compared
presentation by BDCA3+ DCs with BDCA1+ DCs using a quantitative approach whereby
antigens were targeted to distinct intracellular compartments by receptor-mediated …
Human BDCA3+ dendritic cells (DCs), the proposed equivalent to mouse CD8α+ DCs, are widely thought to cross present antigens on MHC class I (MHCI) molecules more efficiently than other DC populations. If true, it is unclear whether this reflects specialization for cross presentation or a generally enhanced ability to present antigens on MHCI. We compared presentation by BDCA3+ DCs with BDCA1+ DCs using a quantitative approach whereby antigens were targeted to distinct intracellular compartments by receptor-mediated internalization. As expected, BDCA3+ DCs were superior at cross presentation of antigens delivered to late endosomes and lysosomes by uptake of anti-DEC205 antibody conjugated to antigen. This difference may reflect a greater efficiency of antigen escape from BDCA3+ DC lysosomes. In contrast, if antigens were delivered to early endosomes through CD40 or CD11c, BDCA1+ DCs were as efficient at cross presentation as BDCA3+ DCs. Because BDCA3+ DCs and BDCA1+ DCs were also equivalent at presenting peptides and endogenously synthesized antigens, BDCA3+ DCs are not likely to possess mechanisms for cross presentation that are specific to this subset. Thus, multiple DC populations may be comparably effective at presenting exogenous antigens to CD8+ T cells as long as the antigen is delivered to early endocytic compartments.
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