This invention provides an isolated strain of Hepatitis B virus designated Human
Hepatitis B Virus Surface Antigen-'-145 Singapore Strain (Glycine to Arginine)
which constituent viral genome is deposited under Accession Nos. P97121504, P97121505
and P97121506 with the European Collection of Cell Culture on 15th Dec. 1997. This
invention also provides an isolated nucleic acid encoding a polypeptide which is
a mutant major surface antigen of a strain of hepatitis B virus, such polypeptide
having an amino acid sequence which differs from the amino acid sequence of a major
surface antigen of a wild type hepatitis B virus in that the amino acid at position
number 145 of such polypeptide is an arginine rather than a glycine, and the purified
peptide. This invention further provides an isolated nucleic acid which encodes
a peptide, wherein the peptide is encoded by a nucleic acid molecule comprising
nucleotides 527 through 595 of SEQ. ID. No. 1, and the purified peptide. This invention
also provides various methods using the disclosed isolated nucleic acids and polypeptides.
This invention also provides various uses of the viral strain and its proteins.