Oxford University Professor Sarah Gilbert has been making and testing vaccines designed to induce T cell responses for ten years, chiefly using antigens from malaria and influenza. Based at the Jenner Institute, several of the vaccines developed in Professor Gilbert’s laboratory have progressed into Clinical Trials.
Prof Ian Jones, Professor of Virology, University of Reading, said:
“The Vaccitech approach, which uses a harmless chimpanzee virus to carry the fragment of SARS-CoV-2 that is required for immunity, has been extensively tested in other situations so there is indeed a good chance it will work as designed. More challenging however will be working out if the amount given is sufficient to give full protection and if it needs one dose or two. Two doses will mean only half the number can be vaccinated with the same batch of vaccine. Any final roll-out will almost certainly need a level of manufacturing the country does not readily have, so transfer to, and liaison with, an external manufacturer may also need to be tackled.
The Vaccitech platform involves delivering either one or two heterologous viral vectors, each encoding the same antigen, several weeks to months apart for the most effective T cell induction.
Vaccitech immunotherapies stimulate strong, durable, and polyfunctional CD8+ and CD4+ T cell responses in humans that are leading with respect to CD8+ T cell magnitude. The responses are characterized by T cells with functional properties naturally associated with viral clearance and tumour protection that will persist for years in the immune system after induction. The treatments are also able to induce potent and durable antibody responses from the humoral arm of the immune system.
The ‘prime’ component uses a non-replicating chimpanzee adenoviral vector encoding a particular pathogen antigen (the part of the invader the immune system will come to recognise) or cancer antigen (the part of a cancer cell that differs from a normal cell). The same antigen is then produced and recognised from another non-replicating viral vector Modified vaccinia Ankara (MVA) which serves to ‘boost’ an immune response to protect against or treat the target disease with exquisite specificity.
Vaccitech is a clinical stage T cell immunotherapy company developing products to treat and prevent infectious disease and cancer.