A multivalent minigene vaccine, containing B-cell, cytotoxic T-lymphocyte, and Th epitopes from several microbes, induces appropriate responses in vivo and confers protection against more than one pathogen

Abstract

The development of safe and effective vaccines remains a major goal in the prevention, and perhaps treatment, of infectious diseases. Ideally, a single vaccine would confer protection against several pathogens and would induce both cellular and humoral arms of the immune response. We originally demonstrated that two virus-specific cytotoxic T-lymphocyte (CTL) epitopes, from the same virus but presented by different major histocompatibility complex alleles, when linked in tandem as minigenes in a recombinant vaccinia virus, could confer complete protection against subsequent viral challenge. In the study, we extended this approach, which we termed string of beads, expanding the immunogenic scope in two ways: first, by introduction of T helper (T h ) and B-cell (antibody) epitopes alongside CTL epitopes and second, by including immunogenic sequences from a variety of infectious agents, five viruses and one bacterium. The vaccine (VV-sv) comprises CTL epitopes from Sendai virus, respiratory syncytial virus, and lymphocytic choriomeningitis virus (LCMV); T h epitopes from vesicular stomatitis virus and Mycobacterium tuberculosis;and an antibody epitope from mengovirus. The construct contains a single start codon, and the epitopes are linked directly, without intervening spacer amino acids. There was some concern that the combination of several normally immunodominant epitopes might result in a new hierarchy of dominance, in which certain epitopes predominated and others exhibited reduced immunogenicity. However we show that when analyzed in tissue culture and in vivo, all six epitopes are expressed. CTL and T h cells are induced in vivo, along with neutralizing antibody. The induced immunity is biologically relevant: after VV-sv immunization, the antimengovirus antibody confers protection against mengovirus challenge. Similarly, CTL induced by the LCMV epitope protected mice against challenge with this agent. Thus, a polyvalent, minigene-based vaccine can simultaneously induce several classes of immune response and thereby can confer protection against diverse pathogens.

Immuno‐informatics: Mining genomes for vaccine components

“…These barriers to understanding and formulating epitope‐driven vaccines notwithstanding, the concept that an ensemble of epitopes in the context of the appropriate delivery vehicle may be able to stimulate a protective response, is driving the development of epitope‐driven vaccines in a large number of laboratories 88 , 89 . Complex vaccines containing Th and B‐cell epitopes alongside CTL epitopes derived from a variety of pathogens (such as five viruses and one bacterium) have already been constructed and tested 90 .…”

“…A typical epitope‐based vaccine construct contains a single start codon with epitopes inserted consecutively in the construct, with or without intervening spacer amino acids. In vitro studies of these constructs have confirmed that the epitopes are expressed, stimulate protective immune responses, and do not interfere withone another 89 , 90 . Another epitope‐driven vaccine approach is to mix several plasmids together, each of which contains genes for different proteins or different minigene epitopes.…”

Genetic vaccination strategies for enhanced cellular, humoral and mucosal immunity

“…Whilst the preceding sections have focused on the development of polytope vaccination strategies for class I MHC-restricted CD8+ CTL, the generation of CD4+ T-cell responses using polytope vaccine technology, partictdarly without the induction of B-cell responses, is also likely to fmd wide application. The ability of polytope constructs to deliver class II MHC-restricted CD4^ T-cell epitopes was originally described by An and colleagues, who delivered Th-cell epitopes in a polytope construct in a recombinant W (82). Whilst this approach was successftil, the simple inclusion of MHC class Il-restricted epitopes in cytoplasmically expressed polytopes delivered by non-lytic vectors, such as DNA vaccines or FPV, is unlikely to reliably generate effective CD4+ T-cell responses in vivo.…”

Induction of a protective capsular polysaccharide antibody response to a multiepitope DNA vaccine encoding a peptide mimic of meningococcal serogroup C capsular polysaccharide

“…47±51 An advantage of this approach is the induction of a multispeci®c immune response directed at various immunologically relevant epitopes. 52,53 The ability to modulate the immune response to speci®c protein and carbohydrate epitopes makes DNA vaccines ideal for use against encapsulated organisms, where antibodies can be directed at both the polysaccharide and relevant protein epitopes. Including epitopes that encode peptide mimics of various serogroup polysaccharides, and those encoding conserved cell-wall components (i.e.…”