[Heterologous epitopes in the central part of the hepatitis B virus core protein].

A set of plasmids was constructed determining synthesis of hybrid proteins with insertions of antigenic determinants of preS1 and preS2 regions of HBV in the middle part of HBcAg. The polypeptides containing the 31-36 or monomeric 94-105 preS1 epitopes were water-soluble and formed particles similar to the 27-nm ones of native HBcAg, possessing antigenic properties of both HBcAg and the inserted epitope, while the hybrids containing 133-143 of preS2 or a trimeric form of the 94-105 preS1 epitope became membrane-bound. Another hybrid encoded by plasmid pPS2M31 contained two regions of HBcAg modification: insertion of amino acids 133-143 a.

[Introduction of heterologous epitopes at the N-terminal part of the hepatitis B core protein].

For investigation of proteins possessing assigned immunological properties, plasmids pPS31-42, pPS1-5, pPS2-17, and pPS1P-30 were constructed encoding the hepatitis B core protein (HBcAg) with N-terminally inserted immunodominant epitopes of preS regions (amino acids 31-36 or 94-105 of preS1, or 133-143 of preS2). Analysis of the hybrid proteins with the use of ELISA and immunoelectron microscopy showed that the insertions did not prevent specific aggregation of the protein molecules, the inserted sequences being exposed on the surface of the particles obtained, and both HBcAg and the corresponding preS determinants were antigenically active.

[Expression in Escherichia coli of hepatitis B virus polymerase and its functional domains].

The plasmids have been constructed permitting expression of hepatitis B viral polymerase and its functional domains, the catalytic and end ones, as hybrid proteins containing 12 alien amino acids in the N-terminal. Immunoblotting with the rabbit antisera to N- and C-terminals of hepatitis B polymerase amino acid sequence has demonstrated that constructed plasmids determine the synthesis of the corresponding proteins in bacterial cells. HBV polymerase is processed in Escherichia coli cells.

[Synthesis and antigenic activity of peptides of the nucleocapsid protein of the hepatitis delta virus].

Hepatitis delta virus (HDV), a recently discovered infectious agent, participates in severe, often lethal forms of acute and chronic hepatitis and liver cirrhosis. Based on theoretical analysis of secondary structure, hydrophilicity and acrophilicity data, several regions of HDV antigen, presumably containing B-epitopes, have been revealed and the corresponding peptides have been synthesized by the solid phase method. All the peptides obtained reacted with the respective antipeptide rabbit sera.

[Synthesis of peptides of the preS1-region of the viral hepatitis B envelope protein and localization of antigenic determinants].

We synthesized the 24-41, 30-36, 31-36, 24-30 fragments of the preS1-region of the hepatitis B (subtype ayw) envelope. The peptides were prepared by the solid phase synthesis on perfluorpolyethylene polymer grafted with polystyrene. The peptide chains were elongated from C-terminus using activated esters and symmetrical anhydrides of Boc-amino acids, cleaved off the solid phase by HBr or TFMSA in TFA, purified by gel filtration, and, after conjugation with protein carriers, inoculated into test animals.