Engineering and characterization of a novel Self Assembling Protein for Toxoplasma peptide vaccine in HLA-A*11:01, HLA-A*02:01 and HLA-B*07:02 transgenic mice.

Fighting smart diseases requires smart vaccines. Novel ways to present protective immunogenic peptide epitopes to human immune systems are needed. Herein, we focus on Self Assembling Protein Nanoparticles (SAPNs) as scaffolds/platforms for vaccine delivery that produce strong immune responses against Toxoplasma gondii in HLA supermotif, transgenic mice. Herein, we present a useful platform to present peptides that elicit CD4, CD8 T and B cell immune responses in a core architecture, formed by flagellin, administered in combination with TLR4 ligand-emulsion (GLA-SE) adjuvant. We demonstrate protection of HLA-A11:01, HLA-A02:01, and HLA-B07:02 mice against toxoplasmosis by (i) this novel chimeric polypeptide, containing epitopes that elicit CD8 T cells, CD4 T helper cells, and IgG2b antibodies, and (ii) adjuvant activation of innate immune TLR4 and TLR5 pathways. HLA-A11:01, HLA-A02:01, and HLA-B07:02q11 transgenic mouse splenocytes with peptides demonstrated predicted genetic restrictions. This creates a new paradigm-shifting vaccine approach to prevent toxoplasmosis, extendable to other diseases.