Joseph Salceda

Optimizing Intein Display on MS2 Virus-Like Particles for Oral Vaccine Delivery

Faculty PI: Carolyn Mills

The need for low-temperature storage throughout the immunization supply chain limits access to life-saving vaccines worldwide. Shelf-stable oral vaccines are a promising candidate for addressing this issue. We proposed a vaccine delivery method consisting of a pill containing  probiotics that produce a nanoparticle-based vaccine inside the patient’s gut. Our nanoparticle is a self-assembling viral capsid derived from the bacteriophage MS2, and we engineer it to display antigens on its surface to immunize against different diseases. We attach antigens to the nanoparticle surface via split inteins, which are protein domains that can connect other protein fragments. We aim to display one half of these split inteins on our viral particle, but fusing these inteins directly onto particle subunits will interfere with self-assembly. To overcome this challenge, we propose using a protein-based linker to space out the intein and particle subunit, but the ideal linker sequence is unknown, and linker design rules have not been clearly established. To determine the optimal linker sequence, we are producing a library of DNA sequences encoding for our protein construct and screening for self-assembling particles via microscopy. Our microscope images depict successfully formed particles, demonstrating that our library contains successful linker sequences. These results indicate that peptide linkers are a viable strategy for surface display on viral nanoparticles, and support our design choice of antigen display via split intein chemistry.