Search

Virus-like particles (VLPs), comprised of viral structural proteins devoid of genetic material, are tunable nanoparticles that can be chemically or genetically engineered, to be used as platforms for multimeric display of foreign antigens. Here, we report the engineering of chimeric VLPs, derived from rabbit hemorrhagic disease virus (RHDV) for presentation of foreign B-cell antigens to the immune system. The RHDV capsid comprises 180 copies of a single capsid subunit (VP60). To evaluate the ability of chimeric RHDV VLPs to elicit protective humoral responses against foreign antigens, we tested two B-cell epitopes a novel neutralizing B-cell epitope, derived from feline calicivirus capsid protein, and a well characterized B-cell epitope from the extracellular domain of influenza A virus M2 protein (M2e). We generated sets of chimeric RHDV VLPs by insertion of the foreign B-cell epitopes at three different locations within VP60 protein (which involved different levels of surface accessibility) and in different copy numbers per site. The immunogenic potential of the chimeric VLPs was analyzed in the mouse model. The results presented here indicated that chimeric RHDV VLPs elicit potent protective humoral responses against displayed foreign B-cell epitopes, demonstrated by both, in vitro neutralization and in vivo protection against a lethal challenge. © The Author(s) 2016.

Virus-like particles (VLPs) are formed by viral structural proteins that, when overexpressed, spontaneously self-assemble into particles that are antigenically indistinguishable from infectious virus or subviral particles. VLPs are appealing as vaccine candidates because their inherent properties (i.e.;virus-sized, multimeric antigens, highly organised and repetitive structure, not infectious) are suitable for the induction of safe and efficient humoral and cellular immune responses. VLP-based vaccines have already been licensed for human and veterinary use, and many more vaccine candidates are currently in late stages of evaluation. Moreover, the development of VLPs as platforms for foreign antigen display has further broadened their potential applicability both as prophylactic and therapeutic vaccines. This chapter provides an overview on the design and use of VLPs for the development of new generation vaccines.

Variable regions of the African swine fever virus genome, which contain arrays of tandem repeats, were compared in the genomes of isolates obtained over a 40-year period. Comparison of the size of products generated by polymerase chain reaction (PCR) from four different genome regions, within the B602L and KP86R genes and intergenic regions J286L and BtSj, placed 43 closely related isolated from Europe, the Caribbean, West and Central Africa into 17 different virus sub-groups. Sequence analysis of the most variable fragment, within the B602L gene, from 81 different isolates distinguished 31 sub-groups of virus isolates which varied in sequence and number of a tandem repeat encoding 4 amino acids. Thus, each of these analysis methods enabled isolates, which were previously grouped together by sequencing of a more conserved genome region, to be separated into multiple sub-groups. This provided additional information about strains of viruses circulating in different countries. The methods could be used in future to study the epidemiology and evolution of virus isolates and to trace the sources of disease outbreaks. © 2006 Springer-Verlag.

Occurrence of vesicular diseases constitutes one of the principal animal health problems in swine. An effective distinction is required between the three viruses causing major indistinguishable vesicular pathologies; two members of the Picornavirus family (foot-and-mouth disease virus - FMDV) and virus causing swine vesicular disease (SVD), as well as vesicular stomatitis virus (VSV), a rhabdovirus that affects the Americas. These three diseases are classified by the OIE (International Office of Epizootics) in the list A, occupying the first three positions in that list. The conventional diagnosis of these viral diseases includes virus isolation using several cell lines and the identification of the agent by ELISA. In the serology usually the prescribed tests for trade, virus neutralisation (VN) and ELISA are used. Although these tests are official and in general allow to carry out a suit diagnosis, the development of new techniques, mainly based on molecular biology, enables to detect these viruses more fastly and with higher specificity and sensibility. Among these tests of new generation can be included polymerase chain reaction (PCR), nucleotide sequence and the use of recombinant proteins.