FIG 4.

A quantification of the population of intact rotavirus particles that bind with host cells. Binding experiments were conducted with the following intact rotavirus concentrations (FFU/ml): 3 × 10³, 6 × 10³, 3 × 10⁴, 6 × 10⁴, and 3 × 10⁵. Human rotavirus samples were inoculated onto MA104 cell monolayers (∼5 × 10⁵ cells) and incubated at 4°C for 1 h. Next, monolayers were washed and lysed, and total RNA was extracted from lysates. Total RNA was subjected to RT-qPCR to amplify and quantify the viral NSP3 gene, which is present as a single copy in each rotavirus virion. The error bars denote the range of duplicate samples tested. The dashed line in the inset shows the lowest copy number measured with the binding assay, about 126 copies.