Functional Implication of Cellular Prion Protein in Antigen-Driven Interactions between T Cells and Dendritic Cells

• Published in: Journal of Immunology Vol. 176; no. 12; pp. 7254 - 7262
• Main Authors: Ballerini, Clara, Gourdain, Pauline, Bachy, Veronique, Blanchard, Nicolas, Levavasseur, Etienne, Gregoire, Sylvie, Fontes, Pascaline, Aucouturier, Pierre, Hivroz, Claire, Carnaud, Claude
• Format: Journal Article
• Language: English
• Published: United States Am Assoc Immnol 15.06.2006
• Subjects: Amino Acid Sequence; Animals; Antigen Presentation - genetics; Cell Adhesion - immunology; Cell Communication - genetics; Cell Communication - immunology; Cell Differentiation - immunology; Cell Membrane - genetics; Cell Membrane - immunology; Cell Membrane - metabolism; Dendritic Cells - cytology; Dendritic Cells - immunology; Dendritic Cells - metabolism; Female; H-Y Antigen - physiology; Lymphocyte Activation - genetics; Lymphocyte Culture Test, Mixed; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Molecular Sequence Data; Prions - biosynthesis; Prions - genetics; Prions - physiology; Receptors, Antigen, T-Cell - genetics; T-Lymphocyte Subsets - cytology; T-Lymphocyte Subsets - immunology; T-Lymphocyte Subsets - metabolism; Up-Regulation - genetics; Up-Regulation - immunology
• ISSN: 0022-1767; 1550-6606; 1365-2567
• DOI: 10.4049/jimmunol.176.12.7254

The cellular prion protein (PrPC) is a host-encoded, GPI-anchored cell surface protein, expressed on a wide range of tissues including neuronal and lymphoreticular cells. PrPC may undergo posttranslational conversion, giving rise to scrapie PrP, the pathogenic conformer considered as responsible for prion diseases. Despite intensive studies, the normal function of PrPC is still enigmatic. Starting from microscope observations showing an accumulation of PrPC at the sites of contact between T cells and Ag-loaded dendritic cells (DC), we have studied the contribution of PrPC in alloantigen and peptide-MHC-driven T/DC interactions. Whereas the absence of PrPC on the DC results in a reduced allogeneic T cell response, its absence on the T cell partner has no apparent effect upon this response. Therefore, PrPC seems to fulfill different functions on the two cell partners forming the synapse. In contrast, PrPC mobilization by Ab reduces the stimulatory properties of DC and the proliferative potential of responding T cells. The contrasted consequences, regarding T cell function, between PrPC deletion and PrPC coating by Abs, suggests that the prion protein acts as a signaling molecule on T cells. Furthermore, our results show that the absence of PrPC has consequences in vivo also, upon the ability of APCs to stimulate proliferative T cell responses. Thus, independent of neurological considerations, some of the evolutionary constraints that may have contributed to the conservation of the Prnp gene in mammalians, could be of immunological origin.