Construction and Immunological Evaluation of Multivalent Hepatitis B Virus (HBV) Core Virus-Like Particles Carrying HBV and HCV Epitopes

Abstract

A multivalent vaccine candidate against hepatitis B virus (HBV) and hepatitis C virus (HCV) infections was constructed on the basis of HBV core (HBc) virus-like particles (VLPs) as carriers. Chimeric VLPs that carried a virus-neutralizing HBV pre-S1 epitope corresponding to amino acids (aa) 20 to 47 in the major immunodominant region (MIR) and a highly conserved N-terminal HCV core epitope corresponding to aa 1 to 60 at the C terminus of the truncated HBc⌬ protein (N-terminal aa 1 to 144 of full-length HBc) were produced in Escherichia coli cells and examined for their antigenicity and immunogenicity. The presence of two different foreign epitopes within the HBc molecule did not interfere with its VLP-forming ability, with the HBV pre-S1 epitope exposed on the surface and the HCV core epitope buried within the VLPs. After immunization of BALB/c mice, specific T-cell activation by both foreign epitopes and a high-titer antibody response against the pre-S1 epitope were found, whereas an antibody response against the HBc carrier was notably suppressed. Both inserted epitopes also induced a specific cytotoxic-T-lymphocyte (CTL) response, as shown by the gamma interferon (IFN-␥) production profile.Genetically engineered virus-like particle (VLP)-based vaccines are one of the most promising tools in modern vaccinology. VLPs from almost all classes of viruses are being evaluated now or have just been adopted to use as carriers for presentation of foreign immunological epitopes (for a review, see references 29 and 31). VLP technologies possess obvious advantages for the generation of safe and efficacious vaccines. First, the repetitive antigenic structure of VLPs makes them highly immunogenic. Second, VLPs lack viral genomes or genes and are noninfectious, although they mimic infectious viruses in their structural and immunological features. Third, VLPs are generated by highly efficient heterologous expression of the cloned viral structural genes with subsequent quantitative in vivo or in vitro self-assembly of their products. Fourth, VLPs can be obtained by simple and efficient purification procedures. VLPs can be used for a broad range of applications, but the generation of vaccines against hepatitis B virus (HBV) and hepatitis C virus (HCV) infections is of special interest.The HBV core (HBc) protein was first reported as a promising VLP carrier in 1986 and was published in 1987 (6, 10, 24). In many ways, HBc occupies a unique position among the VLP carriers because of its high-level synthesis and efficient selfassembly in virtually all known homologous and heterologous expression systems, including bacteria (for a review, see references 29 to 31). The major HBc B-cell epitopes (c and e1) are localized within the major immunodominant region (MIR), whereas the next important epitope, e2, is localized around amino acid position 130, close to the C-terminal histone-like region (for a review, see reference 30).The high-resolution spatial structure of HBc icosahedrons (11,43) shows that the MIR is located on the tip of th...

A VLP Library of C-Terminally Truncated Hepatitis B Core Proteins: Correlation of RNA Encapsidation with a Th1/Th2 Switch in the Immune Responses of Mice

“…As it has been found earlier, HBe antigen, a non-particulate RNA-free analogue of HBc antigen [48], as well as recombinant RNA-free HBc1-144 and HBc1-149 variants from bacteria [36] primed predominantly Th2 immunity, in opposite to full-length RNA-containing HBc1-183, which primed predominantly Th1 immunity. The same Th1/Th2 switch has been described by us for full-length and C-terminally truncated HBc variants carrying HBV preS1 [49] and HCV [47] epitopes.…”

“…In our previous publication, we have chosen the thermal stability as a measure of the VLP stability [47]. Here, we did away with this parameter, since the latter cannot explain processes, which do occur at the constant physiological temperature.…”

Induction of Humoral and Cell-Mediated Immune Responses by Hepatitis B Virus Epitope Displayed on the Virus-Like Particles of Prawn Nodavirus

“…The carriers enhance the antigenicity of the fused epitopes (35)(36)(37), which are often found to be inefficient in eliciting immune responses. In addition, VLPs allow the display of more than a single epitope, enabling the development of multivalent vaccines (25,38,39).…”

Virus-Based Nanoparticles as Versatile Nanomachines

“…Chimeric VLPs display heterologous antigens and can generate antipathogen and neutralizing antibodies such that immunization may also result in protection against pathogen challenge (99, 100). Many studies have been carried out with chimeric VLPs based on plant viruses (101–107), bacteriophages (108, 109), insect viruses (110), and animal polyomaviruses and papillomaviruses (97, 98).…”