BM32 is a grass pollen allergy vaccine based on recombinant fusion proteins consisting of nonallergenic peptides from the IgE-binding sites of the 4 major grass pollen allergens and the hepatitis BpreS protein.
Fusion proteins consisting of nonallergenic peptides from the 4 major timothy grass pollen allergens and the PreS protein from hepatitis B virus as a carrier were expressed in Escherichia coli and purified by means of chromatography.
Of this batch of sera, the preS gene sequence was obtained from HBV DNA from three out of the four blood donors and two out of the three chronic carriers.
In vivo an antisense oligodeoxynucleotide directed against the 5'-region of the preS gene of the duck hepatitis B virus inhibited the viral replication and gene expression in ducks.
To conclude, rearrangements and deletions in the preS gene would potentially lead to an impairment in viral clearance without affecting viral penetration in liver cells, possibly accounting for chronic HBV infection.