Surface expression of the hRSV nucleoprotein impairs immunological synapse formation with T cells

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 111; no. 31; pp. E3214 - E3223
• Main Authors: Céspedes, Pablo F, Bueno, Susan M, Ramírez, Bruno A, Gomez, Roberto S, Riquelme, Sebastián A, Palavecino, Christian E, Mackern-Oberti, Juan Pablo, Mora, Jorge E, Depoil, David, Sacristán, Catarina, Cammer, Michael, Creneguy, Alison, Nguyen, Tuan H, Riedel, Claudia A, Dustin, Michael L, Kalergis, Alexis M
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 05.08.2014; National Acad Sciences
• Series: PNAS Plus
• Subjects: Animals; Biological Sciences; Brefeldin A - pharmacology; CD4-Positive T-Lymphocytes - drug effects; CD4-Positive T-Lymphocytes - immunology; CD4-Positive T-Lymphocytes - pathology; Cell Communication; Cell Line; Cell Membrane - drug effects; Cell Membrane - metabolism; Dendritic Cells - drug effects; Dendritic Cells - metabolism; Golgi Apparatus - drug effects; Golgi Apparatus - metabolism; Histocompatibility Antigens - immunology; Human health and pathology; Human respiratory syncytial virus; Humans; Immunological Synapses - drug effects; Immunological Synapses - immunology; Immunology; Life Sciences; Lipid Bilayers - metabolism; Lipids; Lymphocyte Activation - drug effects; Mice; Mice, Inbred C57BL; Nucleoproteins - metabolism; Peptides - immunology; PNAS Plus; Protein expression; Protein Transport - drug effects; Receptors, Antigen, T-Cell - immunology; Respiratory syncytial virus; Respiratory Syncytial Virus Infections - immunology; Respiratory Syncytial Virus, Human - immunology; Signal transduction; Signal Transduction - drug effects; Signal Transduction - immunology; T cell receptors; Viral Proteins - metabolism; Virus Replication - drug effects; nucleocapsid protein; T lymphocyte priming; pSMAC; cSMAC
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1400760111

Human respiratory syncytial virus (hRSV) is the leading cause of bronchiolitis and pneumonia in young children worldwide. The recurrent hRSV outbreaks and reinfections are the cause of a significant public health burden and associate with an inefficient antiviral immunity, even after disease resolution. Although several mouse- and human cell-based studies have shown that hRSV infection prevents naïve T-cell activation by antigen-presenting cells, the mechanism underlying such inhibition remains unknown. Here, we show that the hRSV nucleoprotein (N) could be at least partially responsible for inhibiting T-cell activation during infection by this virus. Early after infection, the N protein was expressed on the surface of epithelial and dendritic cells, after interacting with trans -Golgi and lysosomal compartments. Further, experiments on supported lipid bilayers loaded with peptide-MHC (pMHC) complexes showed that surface-anchored N protein prevented immunological synapse assembly by naive CD4 ⁺ T cells and, to a lesser extent, by antigen-experienced T-cell blasts. Synapse assembly inhibition was in part due to reduced T-cell receptor (TCR) signaling and pMHC clustering at the T-cell−bilayer interface, suggesting that N protein interferes with pMHC−TCR interactions. Moreover, N protein colocalized with the TCR independently of pMHC, consistent with a possible interaction with TCR complex components. Based on these data, we conclude that hRSV N protein expression at the surface of infected cells inhibits T-cell activation. Our study defines this protein as a major virulence factor that contributes to impairing acquired immunity and enhances susceptibility to reinfection by hRSV.