Primitive CD34⁺/CD38^– and CD34⁺/c-kit⁺ populations are infected by HCMV in vitro. Flow cytometry was used to analyze subpopulations of the CD34⁺ compartment infected with HCMV in vitro. (A) CD38^– and c-kit⁺ cells (gated populations on respective dot plots) constitute 3% and 19% of the CD34⁺ population (gated population on histogram), respectively. (B) CD34⁺/CD38^– and CD34⁺/c-kit⁺ populations are infected with similar efficiency. Histograms indicate the distribution of infected (GFP⁺) cells in the gated region of the preceding dot plot. (C) CD38^– and c-kit⁺ cells within the CD34⁺ compartment are distinct. Only 2% of CD34⁺ cells (gated population on histogram) are c-kit⁺ and CD38^– (dot plot). (D) Lineage-negative cells (gated region on dot plot) expressing the CD34⁺/CD38^– or CD34⁺/c-kit⁺ phenotypes (respective gated regions on dot plots) are infected by HCMV. Histograms indicate the distribution of infected cells (GFP⁺) in the gated populations of the preceding dot plots.