FIG. 4.

Virus binding to TRVb cells expressing feline or canine TfRs. TRVb cells were transfected with plasmids expressing the feline or canine TfR and then incubated for 4 days. The cells were incubated at 37°C for 1 h with Cy5-labeled canine Tf and with 10 μg of FPV, CPV type 2, CPV type 2b, or CPV type 2-G299E capsids/ml and then washed, suspended by EDTA treatment, fixed, and permeabilized. Capsids were detected with Cy2-labeled antibody. Cell associated Tf is shown on the y axis, and virus capsids are shown on the x axis.