FIG 4.

Conditioned medium of feline cells inhibits ERV-DC14 infection and binding. (A) 293T cells incubated for 5 h in conditioned medium (CM) from feline FEA cells or complete DMEM were evaluated for their sensitivity to infection by EGFP retroviral vectors pseudotyped with the ERV-DC14-specific Env or the VSV-G protein. Data are means ± SEM from n = 3 experiments. Student unpaired t test; ****, P ≤ 0.0001. (B) 293T cells from panel A were evaluated for FLVCR1 or CTR1 cell surface expression by flow cytometry using RBD ligands. Numbers (× 10³) indicate the specific delta mean fluorescence intensity of a representative experiment (n = 3).