ABSTRACT
The intracellular hepatitis B surface antigen (HBsAg) content per cell was increased by 7.2-fold in the culture with 1.5% dimethyl sulfoxide (DMSO) compared with that in the control without DMSO, while the extracellular HBsAg production and specific productivity were only improved by 70% and 3.2-fold, respectively. Electron microscope has been employed to reveal large dilated structures within recombinant CHO cells in the presence DMSO. The dilated structures have a distribution within whole cytoplasm, and some dilated areas were engulfed in the nucleus. These large, dilated structures were not observed in the control. Immunogold labeling was used to discover the accumulated HBsAg was localized within these dilated areas, and some HBsAg-specific labels were detected in the nucleus membrane, owing to the encroachment of the dilated areas upon nucleus. The result could help to reveal the mechanism of intracellular HBsAg accumulation in the presence of DMSO.