Polypeptides of hepatitis B surface antigen produced in transgenic potato.

Chimeric genes containing the genomic fragments of hepatitis B virus (HBV) coding for middle (M) and major/small (S) surface proteins were constructed and expressed in transgenic potato plants under the control of the cauliflower mosaic virus 35S promoter. Enzyme-linked immunosorbent assay (ELISA) revealed the presence of HBV surface antigen (HBsAg) determinants in extracts from transgenic plants carrying both constructions, the pre-S2 determinant was identified using the corresponding monoclonal antibodies (mAb) in a dot immunobinding assay. Polypeptides of the immunoaffinity-purified S and M proteins were analyzed by sodium dodecyl sulfate-polyacrylamide-gel electrophoresis. Two polypeptides of the M protein, probably representing different glycosylated forms, and the multimeric forms of HBsAg were observed.