Samuel Ailsworth, MS
Albert Einstein College of Medicine
Development of a B- and T-cell-Stimulating Nanoparticle Vaccine Platform
Self-assembling protein nanoparticles, such as H. pylori Ferritin (Ferr), are established vaccine platforms known to improve antibody responses and CD8+ T-cell activation compared to soluble antigens. To design a platform presenting minimal B- and T-cell epitopes, we engineered a SpyCatcher(SpyC)-Ferr nanoparticle fused to the T-cell-stimulating SIINFEKL peptide (Pep-SpyC-Ferr). To test conjugation of this nanoparticle to a model B-cell immunogen, we expressed Pep-SpyC-Ferr and a SpyTag-fused Zika virus envelope domain III (SpyT-ZDIII) in Expi293 cells, purified the components using Ni-NTA, and conjugated them overnight at a 4:1 ratio (SpyT-ZDIII:Pep-SpyC-Ferr). Nanoparticle formation and conjugation were confirmed by SEC, negative-stain EM, and SDS-PAGE.
To evaluate CD8+ T-cell stimulation, the Pep-SpyC-Ferr component was tested in mice with adjuvants AddaVax and Poly I:C. SIINFEKL-specific CD8+ T cells were passively transferred into C57BL/6 mice (n=2/group), followed by immunization with 15μg or 50μg of Pep-SpyC-Ferr. After 7 days, 4.1% (15μg) and 9.5% (50μg) of CD8+ T cells were activated (CD44+/Ova tetramer+). Control immunizations activated 0.25% (SpyC-Ferr), 0.48% (SIINFEKL Trivax), and 31.6% (Listeria OVA). Without the T-cell transfer, the 50μg Pep-SpyC-Ferr elicited 0.08% activation.
These results show that Pep-SpyC-Ferr nanoparticles induce strong expansion of CD8+ T cells in mice with a large precursor population of peptide-specific naive CD8+ T cells.
Self-assembling protein nanoparticles, such as H. pylori Ferritin (Ferr), are established vaccine platforms known to improve antibody responses and CD8+ T-cell activation compared to soluble antigens. To design a platform presenting minimal B- and T-cell epitopes, we engineered a SpyCatcher(SpyC)-Ferr nanoparticle fused to the T-cell-stimulating SIINFEKL peptide (Pep-SpyC-Ferr). To test conjugation of this nanoparticle to a model B-cell immunogen, we expressed Pep-SpyC-Ferr and a SpyTag-fused Zika virus envelope domain III (SpyT-ZDIII) in Expi293 cells, purified the components using Ni-NTA, and conjugated them overnight at a 4:1 ratio (SpyT-ZDIII:Pep-SpyC-Ferr). Nanoparticle formation and conjugation were confirmed by SEC, negative-stain EM, and SDS-PAGE.
To evaluate CD8+ T-cell stimulation, the Pep-SpyC-Ferr component was tested in mice with adjuvants AddaVax and Poly I:C. SIINFEKL-specific CD8+ T cells were passively transferred into C57BL/6 mice (n=2/group), followed by immunization with 15μg or 50μg of Pep-SpyC-Ferr. After 7 days, 4.1% (15μg) and 9.5% (50μg) of CD8+ T cells were activated (CD44+/Ova tetramer+). Control immunizations activated 0.25% (SpyC-Ferr), 0.48% (SIINFEKL Trivax), and 31.6% (Listeria OVA). Without the T-cell transfer, the 50μg Pep-SpyC-Ferr elicited 0.08% activation.
These results show that Pep-SpyC-Ferr nanoparticles induce strong expansion of CD8+ T cells in mice with a large precursor population of peptide-specific naive CD8+ T cells.
