Synthetic Influenza vaccine (FLU-v) stimulates cell mediated immunity in a double-blind, randomised, placebo-controlled Phase I trial

ObjectivesCurrent Influenza vaccines elicit antibody mediated prophylactic immunity targeted to viral capsid antigens. Despite their global use these vaccines must be administered yearly to the population, cannot be manufactured until the circulating viral strain(s) have been identified and have limited efficacy. A need remains for Influenza vaccines addressing these issues and here we report the results of a Phase Ib trial of a novel synthetic Influenza vaccine (FLU-v) targeting T cell responses to NP, M1 and M2.MethodsForty-eight healthy males aged 18–40 were recruited for this single-centre, randomised, double blind study. Volunteers received one single low (250 μg) or high (500 μg) dose of FLU-v, either alone or adjuvanted. Safety, tolerability and basic immunogenicity (IgG and IFN-γ responses) parameters were assessed pre-vaccination and for 21 days post-vaccination.ResultsFLU-v was found to be safe and well tolerated with no vaccine associated severe adverse events. Dose-dependent IFN-γ responses >2-fold the pre-vaccination level were detected in 80% and 100% of volunteers receiving, respectively, the low and high dose adjuvanted FLU-v formulations. No formulation tested induced any significant FLU-v antibody response.ConclusionFLU-v is safe and induces a vaccine-specific cellular immunity. Cellular immune responses are historically known to control and mitigate infection and illness during natural infection.

► Synthetic FLU-v vaccine targets conserved immunoreactive regions in NP, M1 and M2.
► Phase I trial: One dose of FLU-v, either 250 or 500 μg, with or without adjuvant.
► FLU-v is safe and well tolerated. No vaccine associated severe adverse events.
► Low and high dose adjuvanted FLU-v formulations induce strong cellular immunity.
► FLU-v formulations do not induce significant vaccine-specific antibody responses.