Intracellular distribution of hepatitis B virus core protein expressed in vitro depends on the sequence of the isolate and the serologic pattern

Intracellular localization of hepatitis B core antigen (HBcAg) in vivo varies with liver cell damage. Localization of HBcAg was studied using transfection of cloned HBcAg variants. Twenty-six samples were obtained from 14 patients with liver disease; 10 were hepatitis B e antigen positive, and 16 were anti-hepatitis B e (HBe) positive. In hepatitis B e antigen (HBeAg)-positive patients, HBcAg predominantly localized in the nucleus; in anti-HBe-positive patients, it accumulated mainly in the cytoplasm. Of the 13 samples with nuclear localization, 9 were HBeAg positive; 5 of 13 had C-terminus and/or B cell epitope mutations. All but 1 of the 13 samples with predominantly cytoplasmic localization were anti-HBe positive; all 13 had mutations. Reversion of mutant sequences with cytoplasmic expression back to the wild type led to a shifting back to nuclear distribution. Thus, the pattern of HBcAg localization in vitro depends on sequence and the serologic pattern of chronic infection, paralleling the situation in vivo.