Cryptic association of e antigen with different morphologic forms of hepatitis B surface antigen

Abstract

When highly purified HBsAg particles, separated by rate zonal centrifugation into populations differing in predominant size, were tested for HBeAg, the e1 specificity was detected preferentially in association with particle fractions containing large filaments and Dane particles. These results were obtained both by agar gel diffusion and by radioimmunoassay for e antigen. The e antigen activity present in these fractions was potentiated by prior treatment of particles with Tween 80, suggesting cryptic localization of e1 specificity within or under the outer membrane. The HBeAg released by detergent treatment from a purified preparation composed predominantly of small-particle forms of HBsAg was separated by electrofocusing into a peak of nonparticulate e antigen in the pH range of 5.7--6.0. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed three major polypeptides in this preparation with approximate molecular weights of 25,000, 55,000, and 70,000. Furthermore, two additional peaks of e antigen activity were detected which migrated in association with HBsAg particles at isoelectric points of 4.4 and 5.5--5.6. The major portion of e antigen remained in association with particles after further purification by rate zonal centrifugation.

Detection of two forms of HBeAg (free‐and IgG‐bound HBeAg) in patients with HBe antigenemia using staphylococcus bearing protein A

“…HBe-antigenemia has been considered a marker of viral replication (1,6,15,16), infectivity (17)(18)(19)(20)(21)(22) and poor prognosis (23)(24)(25)(26)(27)(28). In the serum, HBeAg may be found as a simple form (free-HBeAg) with an iso-electric point at pH 4.8 and electrophoretic mobility in the alpha-globulin region, or combined with immunoglobulin G (IgG) (IgG-bound) having an isoelectric point at pH 5.7 and an electrophoretic mobility in the gammaglobulin region (29)(30)(31)(32)(33). It is not clear whether the IgG-bound HBeAg is part of an immune complex or a ligand with affinity for IgG.…”