Multiparametric flow cytometry analysis of peripheral blood B cell trafficking differences among Epstein-Barr virus infected and uninfected subpopulations.

Aims: Epstein-Barr virus (EBV) targets predominantly B cells and these cells could acquire new phenotype characteristics. Here we analyzed whether EBV-infected and -uninfected B cells from healthy subjects differ in proportion of dominant phenotypes, maturation stage, and homing receptors expression.

Methods: EBV-infected and -uninfected cells were identified by flow cytometry using fluorophore-labeled EBV RNA-specific DNA probes combined with fluorophore-labeled antibody to surface lineage markers, integrins, chemokine receptors, and immunoglobulin isotypes, including intracellular ones.

Results: Our results show that the trafficking characteristics of EBER B cells are distinct from EBER B cells with most dominant differences detected for α4β1 and α4β7 and CCR5 and CCR7. EBV-positive cells are predominantly memory IgM B cells or plasmablasts/plasma cells (PB/PC) positive for IgA or less for IgM. In comparison to uninfected B cells, less EBV-positive B cells express α4β7 and almost no cells express α4β1. EBV-positive B cells contained significantly higher proportion of CCR5 and CCR7 cells in comparison to EBV-negative cells. In vitro exposure of blood mononuclear cells to pro-inflammatory cytokine IL-6 reduces population of EBV-positive B cell.

Conclusion: Although EBV-infected B cells represent only a minor subpopulation, their atypical functions could contribute in predisposed person to development abnormities such as some autoimmune diseases or tumors. Using multi-parameter flow cytometry we characterized differences in migration of EBV-positive and -negative B cells of various maturation stage and isotype of produced antibodies particularly different targeting to mucosal tissues of gastrointestinal and respiratory tracts.