Fig 9.

Venus-tagged MYXV uniquely attaches to HuNS1 cells that have little or no surface integrin β1. (A) Differential susceptibility of human multiple myeloma cell lines U266 and HuNS1 to Venus-tagged MYXV versus VACV. U266 or HuNS1 cells were infected with vMyx-Venus/M093 or vVac-Venus/A4 at an MOI of 20.0 at 37°C for 1 h. Unbound virions were removed by washing after adsorption, and cells were further incubated at 37°C. At 4 or 24 h postinfection, cells were fixed and the percentage of virus-infected cells was determined by flow cytometry. Averages of two independent experiments are shown, and the error bars are plotted. Statistical analyses between the two viruses for each cell line were performed using the Student t test. **, P ≤ 0.005, which is considered significant. (B) HuNS1 cells express very little to no integrin β1 on their surface. HeLa, U266, and HuNS1 cells were stained with allophycocyanin-conjugated anti-CD29 at 4°C or left unstained. Unbound antibodies were removed by washing before they were analyzed by flow cytometry. Expression of integrin β1 was examined by measuring the allophycocyanin fluorescence (histograms shown in red). Unstained cells are shown in filled gray histograms.