Low CCR7-Mediated Migration of Human Monocyte Derived Dendritic Cells in Response to Human Respiratory Syncytial Virus and Human Metapneumovirus

Abstract

Human respiratory syncytial virus (HRSV) and, to a lesser extent, human metapneumovirus (HMPV) and human parainfluenza virus type 3 (HPIV3), can re-infect symptomatically throughout life without significant antigenic change, suggestive of incomplete or short-lived immunity. In contrast, re-infection by influenza A virus (IAV) largely depends on antigenic change, suggestive of more complete immunity. Antigen presentation by dendritic cells (DC) is critical in initiating the adaptive immune response. Antigen uptake by DC induces maturational changes that include decreased expression of the chemokine receptors CCR1, CCR2, and CCR5 that maintain DC residence in peripheral tissues, and increased expression of CCR7 that mediates the migration of antigen-bearing DC to lymphatic tissue. We stimulated human monocyte-derived DC (MDDC) with virus and found that, in contrast to HPIV3 and IAV, HMPV and HRSV did not efficiently decrease CCR1, 2, and 5 expression, and did not efficiently increase CCR7 expression. Consistent with the differences in CCR7 mRNA and protein expression, MDDC stimulated with HRSV or HMPV migrated less efficiently to the CCR7 ligand CCL19 than did IAV-stimulated MDDC. Using GFP-expressing recombinant virus, we showed that the subpopulation of MDDC that was robustly infected with HRSV was particularly inefficient in chemokine receptor modulation. HMPV- or HRSV-stimulated MDDC responded to secondary stimulation with bacterial lipopolysaccharide or with a cocktail of proinflammatory cytokines by increasing CCR7 and decreasing CCR1, 2 and 5 expression, and by more efficient migration to CCL19, suggesting that HMPV and HRSV suboptimally stimulate rather than irreversibly inhibit MDDC migration. This also suggests that the low concentration of proinflammatory cytokines released from HRSV- and HMPV-stimulated MDDC is partly responsible for the low CCR7-mediated migration. We propose that inefficient migration of HRSV- and HMPV-stimulated DC to lymphatic tissue contributes to reduced adaptive responses to these viruses.

Human Metapneumovirus SH and G Glycoproteins Inhibit Macropinocytosis-Mediated Entry into Human Dendritic Cells and Reduce CD4 + T Cell Activation

“…As previously described (27), stimulation with UV-inactivated WT (UV-WT) HMPV did not induce appreciable changes in the expression of MDDC maturation markers compared to mock-treated cells. Stimulation with live WT HMPV resulted in a low level of induction and cell surface expression of maturation markers, as previously described (28,44), and this was not significantly changed by deletion of the G and/or SH gene, showing that the G and SH proteins did not detectably influence MDDC maturation (Fig. 2B).…”

Actin-Related Protein 2 (ARP2) and Virus-Induced Filopodia Facilitate Human Respiratory Syncytial Virus Spread

“…UV-inactivated RSV-GFP was prepared using a Stratalinker UV cross-linker (Agilent) at 0.5 J/cm 2 . Complete inactivation was evaluated by plaque assay as described previously [62]. …”

The Mucosal Immune Response to Respiratory Viruses

“…Upon influenza virus infection, DCs rapidly migrate to the DLN (Figure 1) and return to their basal migration level after 48 h, despite ongoing inflammation (Legge and Braciale, 2003). The lack of induction of CCR7 by specific viruses such as human metapneumovirus and human RSV can prevent DCs from migrating to the lymph nodes and thereby hamper the induction of protective responses (Le Nouen et al, 2010;Le Nouen et al, 2011). The roles of the various lung DC subsets in promoting antiviral CD4 and CD8 immunity have been studied best in the context of influenza virus infection (for review see Lambrecht and Hammad, 2012).…”