Valo's PeptiCRAd to coat non-replicating adenovirus expressing COVID-19 Spike Proteins and boost CD8+ T-cell immune response
OXFORD, England and HELSINKI, April 27, 2020 /PRNewswire/ -- Valo Therapeutics Limited (Valo Tx), today announced it 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. It is much faster to manufacture the clinical grade peptides necessary for coating the adenovirus, than re-engineering and manufacturing a new virus, making this approach more flexible and enabling clinical testing to progress quickly in the event that a new coronavirus strain emerges.
Professor Vincenzo Cerullo, Founder and board member of Valo Tx, commented, "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) we expect to further enhance the cell mediated immune response; with the added capacity to broaden the immune targets.
Boosting the cell-mediated immune response in addition to antibody production should enhance prevention and may be more likely to break through the problem of immune senescence in elderly people, who are at most at risk from COVID-19.
About Valo Tx
Valo Therapeutics (Helsinki and Oxford) is an immuno-oncology company with a novel noncovalent virus-coating technology that drives a cell-mediated, in particular a CD-8+ T-cell, immune response to clear cancer cells that express abnormal proteins, or "targets", on their cell surface. This technology (called PeptiCRAd) can be rapidly adapted to target virally infected cells, since the infected cells typically express viral proteins on their surface that are seen as "non-self" targets for clearance by the immune system. Coronaviruses have spike proteins on their outer coats, and immune responses from previous coronavirus studies (resulting from the SARS and MERS outbreaks) suggest that these are a good target for a vaccine.
The Valo Tx platform, PeptiCRAd (Peptide-coated Conditionally Replicating Adenovirus), was developed out of the laboratory of Professor Vincenzo Cerullo at the University of Helsinki. It turns oncolytic adenoviruses into targeted tissue specific cancer vaccines without the need to generate and manufacture multiple genetically modified viruses. A film explaining the PeptiCRAd technology can be found here.
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