Rab22a controls the intracellular trafficking of MHC-I molecules and antigen cross presentation by dendritic cells

CEBRIAN, I; CROCE, C; BLANCHARD, N; MAYORGA, LS

Andover NH

Congreso; Gordon Research Conference:Molecular Membrane Biology; 2015

GRC

Cross presentation is the process by which exogenous antigens are processed and presented to the class I molecules of histocompatibility complex (MHC) to activate a CD8+ T cell response. Dendritic cells (DCs) have been shown to be the most adapted antigen presenting cells to perform efficiently cross presentation. To do this, DCs have developed a strong specialization of their internalization pathway. In this study, we show that recycling compartments play an important role during antigen cross presentation by modulating the intracellular trafficking of MHC-I molecules. In this sense, we observed that the small GTPase Rab22a, which has been previously described to be involved in the recycling of MHC-I molecules, is early recruited to endosomes and phagosomes in DCs. Furthermore, after silencing the expression of Rab22a DCs fail to cross present efficiently either soluble ovalbumin (OVA) or two different antigens from the intracellular parasite Toxoplasma gondii. Altogether, these results evidence a critical role for Rab22a in antigen cross presentation and point it out as a potential target for immunotherapy.