Evaluation of HBs, HBc, and frCP virus-like particles for expression of human papillomavirus 16 E7 oncoprotein epitopes.

Objectives: In an attempt to develop virus-like particles (VLPs) as experimental vaccine against human papilloma virus (HPV)-induced tumours, the HPV16 E7 oncoprotein epitopes spanning amino acid (aa) residues 35-98 were expressed on three proteins capable of VLP formation: hepatitis B virus (HBV) surface (HBs) and core (HBc) antigens, and RNA phage fr coats (frCP).

Methods: The profile of immunoglobulin isotypes induced in Balb/C mice after immunization with purified chimeric proteins was studied.

Results: The HBs*-E7(35-54) protein expressing E7 residues 35-54 between residues 139 and 142 of the HBs carrier formed HBs-like particles in Saccharomyces cerevisiae.

Monoclonal anti-fosB antibody specific for predetermined, nonstructural region of the fosB protein.

Comparison of the primary structures and theoretical prediction of the potential antigenic determinant of the deduced Fos proteins reveals the presence of a nonstructural and hydrophilic region juxtaposed to the leucine zipper and nonconserved among the Fos protein family. To develop monoclonal anti-peptide antibodies capable of distinguishing all Fos-proteins, synthetic peptides specific for the mentioned predicted region were synthesized manually by the "tea-bag" method. Immunization of Balb/c mice with fosB-related synthetic peptide BSA gave rise to mouse hybridoma cell line K21 (IgG1, kappa) secreting highly specific antibodies against corresponding human fosB protein.

RNA phage Q beta coat protein as a carrier for foreign epitopes.

The Q beta gene C has been proposed as a new carrier for the exposure of foreign peptide sequences. Contrary to well-known 'display vectors' on the basis of coat proteins of RNA phage group I, group III phage Q beta-based vectors suggested application of the 195-amino acid extension of coat protein (CP) within the so-called A1 protein for insertion of the appropriate immunological epitopes. 'Mosaic' capsids presenting model hepatitis B virus preS1 and HIV-1 gp120 epitopes and formed by Q beta CP together with A1-derived proteins were obtained as a result of (1) suppression of leaky UGA stop codon of the CP gene and (2) simultaneous expression of 'pure' CP and full-length A1-derived genes obtained after the changing of CP-terminating UGA to strong UAA stop codon or sense GGA codon, respectively.

Locations of antibody binding sites within conserved regions of the hepatitis C virus core protein.

The binding sites for human antibodies recognising antigenic domains within the hepatitis C virus (HCV) core protein were analyzed using synthetic peptides. Omission peptide analogues where a pair of residues was sequentially omitted were produced corresponding to the regions 1-18, 11-28, 21-38, 51-68, and 101-118. The N-terminal part of HCV core was found to contain three distinct antibody binding sites, which includes the previously reported one at residues 9-16.