A flow-FISH assay for the quantitative analysis of parvovirus B19 infected cells

Human parvovirus B19 (B19V) replication is a process highly dependent on the cellular environment, therefore methodologies allowing for analysis at single cell level could represent effective tools to understand cell-to cell differences in the replication process and to investigate cell-virus interactions. Fluorescence in situ hybridization (FISH) can be combined with flow cytometry (flow-FISH) to enable the detection of target nucleic acid sequences in thousands of individual cells in a short amount of time. In the present study, a flow-FISH assay based on the use of a digoxigenin-labeled genomic probe has been developed to discriminate B19V infected cells following in vitro infection of UT7/EpoS1 cell line and EPCs (erythroid progenitor cells) generated from peripheral blood mononuclear cells. In B19V infected UT7/EpoS1 and EPCs, viral nucleic acids were detected by the flow-FISH assay starting from 24 hpi up to 48 hpi. The method, used together with quantitative PCR techniques, can be very useful to describe the kinetics of B19V infection within a heterogeneous cell population.