Developing a pan-coronavirus vaccine

OXFORD, U.K. & HELSINKI, Finland—Valo Therapeutics Ltd. is working to develop a potential novel COVID-19 vaccine with applications across future pandemics. Valo Tx will use its PeptiCRAd technology to coat an undisclosed adenovirus vaccine vector, engineered to express coronavirus associated spike proteins, with HLA-matched peptides optimised to further boost CD8+ T cell immune responses.

Both components of the proposed vaccine have been tested in the past, albeit individually. Non-replicating adenoviruses have been through clinical safety-testing and adenoviral vectors in general have been used safely in thousands of people across a wide range of ages, Valo notes. The company adds that it is much faster to manufacture the clinical grade peptides necessary for coating the adenovirus, as opposed to re-engineering and manufacturing a new virus, making this approach potentially more flexible and enabling clinical testing to progress quickly in the event that a new coronavirus strain emerges.

Saiif Prof. Vincenzo Cerullo, founder and board member of Valo: "There is a pressing need for a COVID-19 vaccine, and a pan-coronavirus vaccine to address a potential future outbreak. We believe our PeptiCRAd technology is rapidly adaptable to the emergence of a new strain or even an entirely new coronavirus.  We believe that by working together with vaccinology partners already developing adenoviruses transfected with SARS-COV-2 spike protein, using our innovative technologies we can actively help to address this global challenge."

Most vaccines focus on boosting the antibody B cells response, but a T cell immune response is important given that the infection targets the respiratory tract. COVID-19, like other coronaviruses, replicates particularly fast and it appears that, by the time neutralizing antibodies are produced, many cells in the lungs have already become infected and require cell-mediated clearance. Adenoviral vectors are particularly strong at inducing T cell mediated immune responses, and it is hoped that the SARS-COV-2 spike proteins will be processed to induce both T-cell and antibody mediated immunity to COVID-19. By additionally coating the adenovirus with peptides specifically selected for driving CD-8+ T cells (through MHC class 1 presentation), the company expects to further enhance the cell mediated immune response; with the added capacity to broaden the immune targets.