Distinct migratory pattern of naive and effector T cells through the blood\u2013CSF barrier following Echovirus 30 infection

Marie Wiatr,Christel Weiss,Jorma Ilonen,Hiroshi Ishikawa,Daniela Latorre,Stefanie Uhlig,Horst Schroten,Tobias Tenenbaum,Britta Engelhardt,Henriette Rudolph,Christian Schwerk,Carolin Stump-Guthier

doi:10.1186/s12974-019-1626-x

Abstract

BackgroundEchovirus 30 (E-30) is one of the most frequently isolated pathogens in aseptic meningitis worldwide. To gain access to the central nervous system (CNS), E-30 and immune cells have to cross one of the two main barriers of the CNS, the epithelial blood–cerebrospinal fluid barrier (BCSFB) or the endothelial blood–brain barrier (BBB). In an in vitro model of the BCSFB, it has been shown that E-30 can infect human immortalized brain choroid plexus papilloma (HIBCPP) cells.MethodsIn this study we investigated the migration of different T cell subpopulations, naive and effector T cells, through HIBCPP cells during E-30 infection. Effects of E-30 infection and the migration process were evaluated via immunofluorescence and flow cytometry analysis, as well as transepithelial resistance and dextran flux measurement.ResultsTh1 effector cells and enterovirus-specific effector T cells migrated through HIBCPP cells more efficiently than naive CD4+ T cells following E-30 infection of HIBCPP cells. Among the different naive T cell populations, CD8+ T cells crossed the E-30-infected HIBCPP cell layer in a significantly higher number than CD4+ T cells. A large amount of effector T cells also remained attached to the basolateral side of the HIBCPP cells compared with naive T cells. Analysis of HIBCPP barrier function showed significant alteration after E-30 infection and trans- as well as paracellular migration of T cells independent of the respective subpopulation. Morphologic analysis of migrating T cells revealed that a polarized phenotype was induced by the chemokine CXCL12, but reversed to a round phenotype after E-30 infection. Further characterization of migrating Th1 effector cells revealed a downregulation of surface adhesion proteins such as LFA-1 PSGL-1, CD44, and CD49d.ConclusionTaken together these results suggest that naive CD8+ and Th1 effector cells are highly efficient to migrate through the BCSFB in an inflammatory environment. The T cell phenotype is modified during the migration process through HIBCPP cells.

Highlights

Echovirus 30 (E-30) is one of the most frequently isolated pathogens in aseptic meningitis worldwide
Increased migration of Th1 effector cells compared with naive T cells through human immortalized brain choroid plexus papilloma (HIBCPP) cells after E-30 infection Previous studies have shown the capacity of naive CD3+ T cells and polymorphonuclear neutrophils (PMN) to migrate across the in vitro model of HIBCPP cells after E-30 infection [31]
CXCL12, a cerebrospinal fluid (CSF) chemokine, which is upregulated during neuroinflammation and is known to promote leukocyte migration, was added or not to the apical side of HIBCPP cells (Fig. 1)

Summary

Introduction

Echovirus 30 (E-30) is one of the most frequently isolated pathogens in aseptic meningitis worldwide. Clinical studies revealed that enterovirus infection of the central nervous system (CNS) resulted in increased levels of inflammatory cytokines within the cerebrospinal fluid (CSF), such as INF-γ, IL-6, and CXCL12 [8, 9], accompanied by influx of neutrophils and T cells [4]. At the beginning of NPEV-caused meningitis, an abundant concentration of polymorphonuclear neutrophils (PMN) and T cells were detected in the CSF of patients [10], especially IFN-γ-producing Th1 cells can be found in the course of disease [11]. Their secretion of high levels of INF-γ enhances the activation of other immune cells such as macrophages and dendritic cells. In the resolving phase of the disease, a switch from Th1 to Th2 producing IL-4, IL-5, and IL-13 cells is observed [12]

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Discussion

Conclusion