Polypeptide micelles with relative molecular weights of 25,000 (p25) and 30,000 (gp30) daltons were prepared from native 22-nm hepatitis B surface antigen (HBsAg) particles. This p25/gp30 complex was alum-adsorbed, and three dosage levels (20 micrograms, 4 micrograms, and 0.8 micrograms) were administered at 0, 1, and 6 months to 51 human volunteers. Local and systemic reactions were clinically insignificant, and all vaccinees seroconverted, regardless of dose. As anticipated, antibody responses diminished as the dosage was reduced. Seroconversion rates and geometric mean antibody levels for the 20 micrograms dosage group were significantly better than those observed with a commercial vaccine and were comparable to those achieved after immunization with 40 micrograms of the intact 22-nm particles used to prepare the polypeptides. By 2 weeks, an anti-HBs response was elicited in 80% of the group receiving 20 micrograms of the polypeptide vaccine. This rapid response to immunization may be particularly beneficial for postexposure prophylaxis where the early development of immunity is advantageous.

No abstract

The morphological forms of hepatitis B antigen (HBsAg) present in an HBsAg-positive plasma (15–25 nm spheres, filaments 20–22 nm in diameter and 80–300 nm in length, and 42 nm Dane particles) were isolated and characterized biophysically. The HBsAg in this plasma was fractionated into five distinct populations, containing predominately 15–19 nm spheres, 20–22 nm spheres, 20 × 300 nm filaments, a mixture containing 23–25 nm spheres and rare filaments, and 42 nm Dane particles, respectively. These populations were labeled with 125I and electrofocused in a pH ampholyte gradient. Each population had a distinct isoelectric pH with values ranging from 3.65 to 4.70. Sodium dodecyl sulfate polyacrylamide gel electrophoretic analysis of each of the above labeled populations revealed the presence of 7, 10, 9, 5, and 9 polypeptides, respectively. The population containing predominately 23–25 nm spheres failed to react with antibody specific for HBsAg and probably was composed of inner cores of the Dane particles.

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.