Flow cytometric analysis of β-galactosidase expression in cells derived from thrombopoietin-stimulated CD34⁺cell cultures after infection with Towne/Lox2 strain of HCMV.

Cells cultured in the presence of TPO were directly subjected to flow cytometric analysis without magnetic bead purification step (as in Figure 3). In the side-versus-forward scatter histograms, gates (not shown) were set to exclude nonviable cells to decrease the background staining associated with dead cells. Log PE fluorescence intensity (CD42a or IgG₂ for control) versus log FITC fluorescence intensity (FDG-FITC). (A-D) Staining results of HCMV infection of megakaryocytes generated in cultures of CD34⁺ cells challenged with HCMV on day 0. (A) Mock-infected cells, PE-conjugated IgG₂ versus FDG-FITC. (B) HCMV-infected cells, PE-conjugated IgG₂ versus FDG-FITC. (C) Mock-infected cells, PE-conjugated CD42a versus FDG-FITC. (D) HCMV-infected cells, PE-conjugated CD42a versus FDG-FITC. (E, F) Cultures challenged with HCMV after megakaryocytes appeared in the cultures. Numbers of CD42a⁺ cells were lower than those shown in panels C and D because of the higher number of nonviable cells excluded by gating. This effect was markedly pronounced in HCMV-infected cultures. (E) Mock-infected cells, PE-conjugated CD42a versus FDG-FITC. (F) HCMV-infected cells, PE-conjugated CD42a versus FDG-FITC.