Influenza A infection causes annual substantial morbidity and mortality worldwide, particularly for infants, the elderly, and the immuncompromised. Current vaccines, such as the parenterally administered trivalent inactivated vaccine (TIV) are administered either unadjuvanted or adjuvanted with aluminum hydroxide (alum). The efficacy of these vaccines is highly dependent on close matching of the hemagglutinin (HA) and neuraminidase (NA) surface proteins of the vaccine with currently circulating virus. Should neutralizing antibody fail to prevent infection of the respiratory tract, subsequent clearance of viral infection is mainly dependent on T cells, particularly cytolytic T lymphocytes (CTL) of the CD8+ T-cell subset. Juvaris BioTherapeutics is developing and characterizing a unique adjuvant that is particularly promising for vaccines that induce both high levels of antibody and T-cell immunity, including CTL. The adjuvant is based on a cationic lipid carrier and non-coding DNA complex (CLDC). Inclusion of protein antigens with CLDC results in an extremely robust humoral and CD4+ and CD8+ T-cell response. The unique aspect of the CLDC adjuvant is that it functions both as a delivery system that targets associated antigens to antigen presenting cells via the liposome component and an immunostimulatory adjuvant via the plasmid DNA. The final product resulting from this proposal is the completion of pre-clinical evaluation and development of the CLDC product for use as an adjuvant in viral vaccines and specifically for influenza. The product development strategy for the CLDC adjuvant in influenza is focused on the exploitation of the near-term opportunity of adjuvanting currently approved vaccines (in the U.S. and abroad) while recognizing the potential of recombinant vaccine approaches currently being evaluated. The specific goals of this proposal are to: 1) Establish limits on adjuvant and vaccine preparation and storage; 2) Optimization of dose; 3) Comparison of the magnitude and durability of the immune response following CLDC/Ag vaccination with existing adjuvants or no adjuvants; 4) Determine mechanism of action of the adjuvant in inducing adaptive immunity in mouse and non-human primate; 5) extent of heterosubtypic protection with CLDC adjuvanted monovalent split vaccines, which will be prepared in house, or monovalent whole inactivated vaccine virus. There is significant evidence that heterosubtypic immunity may follow natural infection and, to a lesser extent, current vaccination strategies. Such immunity will likely be markedly enhanced using CLDC adjuvanted vaccines, but a formal demonstration of this in mice and non-human primates is required before vaccine strategies invoking this mechanism can be clinically tested and adopted for general application.
