FIG 3.

Progesterone pretreatment of Huh7-S10-3 human liver cell enhanced HEV replication as determined by IFA of HEV capsid protein and virus infectivity assay. (A) Representative images of immunofluorescence (two different fields) of HEV ORF2 capsid protein in HEV-P6 transfected Huh7-S10-3 cells, at D5 post-HEV transfection, in the presence or absence of 80 nM PRO. Nuclei are counterstained using DAPI. The inset bar diagram represents intracellular HEV RNA levels determined during the experiment. CC, “cell-control” without HEV transfection. (B and D) Infectious HEV titers as determined by an HEV infectivity assay. (C) HEV negative-strand RNA levels as determined by HEV negative-strand RNA RT-qPCR. (E) Cell proliferation level determined by a WST-1 assay. Data represent an average ± SEM from panels B (n = 2), C (n = 5), D (n = 3 independent experiments), and E (n = 6 replicates); Student’s t test; *, P ≤ 0.05; **, P ≤ 0.01 compared to P6. Progesterone final concentrations are 80 nM PRO = 25 ng/ml, 160 nM PRO = 50ng/ml, 480 nM = 150 ng/ml.