The new HEV EIA developed in the present study is a highly specific diagnostic assay for the detection of anti-HEV activity in serum specimens obtained from different epidemiologic settings.

Hepatitis B core antigen (HBcAg) was purified from Dane particles and from infected hepatocytes. An identical isoelectric pH of 4.0 was determined for labeled preparations of both Dane-derived and liver-derived HBcAg. Unlabeled liver-derived HBcAg demonstrated a lower isoelectric pH of 3.7. Molecular weight determinations by Sepharose 4B column chromatography revealed that liver-derived HBcAg had a molecular weight of 8.5–9.0 × 106 daltons. The sedimentation coefficient of both Dane- and liver-derived HBcAg was found to be 124S. PAGE revealed that iodinated HBcAg derived from Dane particles was very similar in polypeptide structure to HBcAg derived from infected liver tissue. Twelve polypeptides were resolved from Dane core particles, and seven to nine were resolved from liver core particles. Several of the polypeptides in both preparations co-migrated with iodinated hepatitis B surface antigen (HBsAg). However, three polypeptides (mol. wt. 88,000, 79,000 and 59,000) were found in both Dane- and liver-derived HBcAg but not in HBsAg, which suggests that these polypeptides are HBcAg-specific. Endogenous DNA polymerase activity was observed in both Dane- and liver-derived core particles.

The purification is described of liver-derived hepatitis B core antigen (HBe Ag) from human hepatocytes demonstrating only intranuclear particles by electron microscopy. The purified preparation contained 5 × 10u particles per ml. The particles were mono-dispersed and relatively free of background material. DNA-dependent polymerase activity was present and had greater activity than an equal number of cores derived from Dane particles isolated from plasma. Specificity of the polymerase reaction was confirmed by precipitation of the activity with specific anti-HBc antiserum. A proportion of the liver-derived core particles was nonreactive for DNA polymerase activity. The polymerase-positive population of particles had a larger size than the polymerase-negative population of liver-derived cores as evidenced by gel filtration in Sepharose 4B.

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