Selective control of crosspresentation in CD8+ and CD8- dendritic cells subpopulations

ARIEL SAVINA; AUDREY PERES; IGNACIO CEBRIAN; NUNO CARMO; CATARINA MOITA; NIR HACOHEN; LUIS F. MOITA; SEBASTIAN AMIGORENA

Lucca, Barga

Congreso; Gordon Research Conferences: Antigen Cross-Presentation; 2009

GRC

The crosspresentation process to initiate cytotoxic immune responses is selectively performed by a subpopulation of spleen dendritic cells (DCs) known as CD8+ DCs. The NADPH oxidase complex (NOX2) is crucial for regulating the phagosomal pH and allowing extracellular antigens to be efficiently crosspresented. In this study, we showed that the small GTPase Rac2 plays a critical role in crosspresentation by determining the assembly of the NOX2 to phagosomes only in CD8+ DCs subsets. In the absence of Rac2, the production of reactive oxygen species (ROS) in DC-phagosomes was abolished, the phagosomal pH dropped, and the efficiency of antigen crosspresentation was reduced. We conclude that the activity of Rac2 control crosspresentation exclusively in CD8+ DCs through the regulation of phagosomal oxidation and pH.