Fig. 3

Analysis of HCMV progeny from THP-1 latency and reactivation models: IE antigen immunofluorescence pattern. a and c MRC5 fibroblasts were infected with the cell culture medium derived from THP-1 monocytes (“IE-positive MRC5 from THP-1 latency model”) and THP-1 macrophages (“IE-positive MRC5 from THP-1 reactivation model”) which had been infected with TB40E (a) or Towne (c) HCMV strains at MOI of 0.5 (panels a, a’), 0.25 (panels b, b’) or 0.125 (panels c, c’) for 7 days. At 24 h p.i., MRC5 cells were fixed and labelled with a monoclonal antibody specific for the common epitope encoded by exon 2 of HCMV IE1 and IE2 genes. The immunoreaction was revealed by Alexa-Fluor FITC-conjugated goat anti-mouse IgG (panels a, b, c, d: FITC, green nuclei). Cells were counterstained with Evans blue (panels a, b, c, d: red cells) and DAPI (panels a’, b’, c’, d’: blue nuclei). Panels d, d’: uninfected cells. Images were collected using a conventional fluorescence microscopy. Bar: 25 μm. b and d The quantitative evaluation of IE-positive MRC5 fibroblasts infected with the cell culture medium derived from TB40E (b) or Towne (d) reactivation models. Values were expressed as mean percentages of IE-positive cells per field (ten randomly selected fields per slide were counted) from two independent experiments; error bars indicate standard deviations. Values were processed using GraphPad Prism 7 software