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 self-assembling 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-γ 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.