The company will use its peptide-coated conditionally replicating adenovirus (PeptiCRAd) technology to coat an adenovirus vector, engineered to express coronavirus spike proteins with human leukocyte antigen-matched peptides that boost CD8+ T-cell immune responses. Both components had to be tested individually in the past, and the company believes that it will be much quicker to manufacture clinical-grade peptides for coating an adenoviral vector rather than reengineering a new virus. Moreover, this approach allows flexibility and rapid clinical testing if a new coronavirus strain emerges.

A T-cell vaccine could be useful, according to the company, because coronaviruses produce neutralizing antibodies that require cell-mediated clearance. The company hopes that the combination of adenoviral vectors will produce strong T-cell mediated immune responses and that the SARS-CoV-2 spike proteins will produce antibody-mediated immune responses. The additional coating with selected peptides will serve to further boost the cell-mediated response and broaden the immune targets.