Specific Aims:

1. Which HBV envelope proteins can provide

the assembly of HDV?

2. Which HBV envelope proteins is necessary

for infectious HDV?

Experimental Flow Chart

1. Prepared stable cell lines expressed 3

kinds of HBV envelope proteins:

S-:HBV S protein only; SM-:HBV S and M

proteins; SML-:HBV S,M and L proteins

î

2. Transfected HDV Plasmid into 3 stable cell

lines: S-HDV, SM-HDV and SML-HDV

î

3. Immunoblotting Analysis all cell lines

expressed HBsAg and HDsAg

î

4. Purified HDV particle from 3 stable cell

lines culture media by CsCl gradient and

verified HDV particle characteristics

î

5. The 3 HDV particles in vitro infected to

primary cultures of chimpanzee

hepatocytes. To verified which protein is

required for HDV infectivity

Conclusion:

1. HDV particle can be assembled in the

presence of the S envelope protein only.

2. HBV L envelope protein is necessary for

infectivity of HDV.

3. HBV does not provide a helper function in

the replication of HDV RNA.

4. HBV is only required to provide the

envelope proteins for particle assembly,

one of which appears to be the HDV

receptor binding site.

Discussion:

1. Pre-S1 polypeptides may be also the

receptor-binding site for HDV

2. Without HBV helper, cells may contain RNA-

dependent RNA Polymerase to offer HDV RNA

replication since delta Ag is too small to

encode a polymerase.

circular, double-strand

3.2 Kbp DNA

negative strand 1.7Kbp RNA