Effectiveness of a novel immunogenic nanoparticle platform for Toxoplasma peptide vaccine in HLA transgenic mice

We created and produced a novel self-assembling nanoparticle platform for delivery of peptide epitopes that induces CD8(+) and CD4(+)T cells that are protective against Toxoplasma gondii infection. These selfassembling polypeptide nanoparticles (SAPNs) are composed of linear peptide (LP) monomers which contain two coiled-coil oligomerization domains, the dense granule 7 (GRA7(20-28) LPQFATAAT) peptide and a universal CD4(+)T cell epitope (derived from PADRE). Purified LPs assemble into nanoparticles with icosahedral symmetry, similar to the capsids of small viruses. These particles were evaluated for their efficacy in eliciting IFN-gamma by splenocytes of HLA-B(*)0702 transgenic mice and for their ability to protect against subsequent T. gondii challenge. This work demonstrates the feasibility of using this platform approach with a CD8(+) epitope that binds HLA-B7 and tests the biological activity of potentially protective peptides restricted by human major histocompatibility complex (HLA) class I molecules in HLA transgenic mice. (C) 2014 Elsevier Ltd. All rights reserved.