FIG 4.

Tva with L55/W69 substitution lost its ability to mediate ALV-A infection. (A and B) Entry of RCASBP(A) virus into DF-1-TvaKO cells expressing Tva with L55/W69 substitution. wtTva was used as a positive control, and huCD320 was used as a negative control. (A) Virus entry levels as analyzed by fluorescence microscopy at 72 hpi. Scale bar: 125 μm. (B) Virus entry levels as analyzed by counting the proportion of GFP-positive cells using a flow cytometric at 72 hpi. (C) gp85-Binding abilities of the chimeric Tva receptors expressed on DF-1-TvaKO cells as evaluated by receptor binding assays. (D) Physical interactions between the chimeric Tva receptors (with an Fc tag) and gp85 (with a Flag tag) as determined by Co-IP assays in 293T cells. Data from three independent experiments are shown as means ± standard deviations of triplicates. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ns, no significant difference.