Fig 2.

TEM analysis of HBV-infected DMSO-treated HuS-E/2 cells and collection of secreted HBV particles. (A to C) TEM images of DMSO-treated HuS-E/2 cells producing HBV particles. Twenty hours after infection with HBV, DMSO-treated HuS-E/2 cells were washed and then incubated for 10 days, when immunogold labeling of HBsAg was performed using polyclonal anti-HBsAg antibodies, followed by secondary antibody coupled to 18-nm-diameter gold particles, and images were obtained by TEM. Black arrows, HBsAg at the ER (A) and intact HBV particles at the plasma membrane (B); white arrows, ER region in noninfected cells (C). N, nucleus; ER, endoplasmic reticulum; Cy, cytoplasm; PM, plasma membrane. (D) Western blot analysis of HBV particles secreted from HBV-infected DMSO-treated HuS-E/2 cells. DMSO-treated HuS-E/2 cells were infected with HBV for 20 h, washed with PBS, and incubated for a further 12 days. The culture medium was changed and collected every 4 days, and the samples were pooled and centrifuged to concentrate the virus particles as described in Materials and Methods. Western blot analysis was performed using anti-HBsAg antibodies. Lane −, noninfected cells as a control.