Hepatitis B virus Dane particles bind to human plasma apolipoprotein H

Human apolipoprotein H (apo H) was found to bind specifically to hepatitis B surface antigen (HBsAg) from hepatitis B virus (HBV)-infected individuals . We used recombinant HBsAg proteins to analyze HBV domains recognized by a po H. We showed that the myristylated pre-Si domain of HBsAg strongly inter acted with apo H, This binding involved phospholipid components of the HBV envelope because their removal by detergent prevented apo H-HBsAg interacti on. The opposite effects of iron and zinc metal ions on binding suggest tha t the oxidation of phospholipids also affects apo H-HBsAg interaction. Afte r fractionation of viral particles on a sucrose gradient, and their additio n to microtiter plates coated with apo H or anti-HBsAg, we observed that th e maximal anti-HBsAg capture activity corresponded to a sucrose concentrati on of 36%, whereas the maximal apo H capture activity corresponded to a con centration of 39%. Electron microscopy and polymerase chain reaction (PCR) Southern blot studies of these fractions showed that the fraction with maxi mal apo H binding predominantly contained full Dane particles. Finally, we studied apo H-HBsAg binding relative to the presence of hepatitis B virus m arkers and observed that apo H binding activity for HBsAg was higher in ser a from patients in the active virus replication phase.