Polypeptides of hepatitis B virus surface antigen produced by a hepatoma cell line

Abstract

The PLC/PRF/5 cell line derived from a human hepatoma produces hepatitis B surface antigen (HBsAg) in 22 nm particles of the same buoyant density as those found in the serum of infected patients. The HBsAg particles from this cell line were labeled with [35S]methionine and purified, and the polypeptides were compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis with those of serum-derived particles. The 2 major polypeptides of serum-derived HBsAg particles (p20 and p23) were found in the same relative amounts in the particles from the cell line. The 3 smallest of the 5 minor components observed in HBsAg particles from serum were present in particles from the cell line. These polypeptides (p31, p36 and p43) and p20 and p23 were precipitated with anti-HBs-containing serum. The 2 largest polypeptides of serum particles (p49 and p66) were not detected in particles from these cells. When the PLC/PRF/5 HBsAg particles were radiolabeled with tritiated sugars, p23, and not p20, contained radioactivity, indicating that the pattern of polypeptide glycosylation is similar to that or serum HBsAg. No other possible gene product of hepatitis B virus was detected in the PLC/PRF/5-derived HBsAg particles, in the cells or in the cell supernatants.