Discovery of Cell Intrinsic Immunologic Adjuvants for Improving Self Amplifying RNA Vaccines Against Infectious Diseases

Project Summary The COVID-19 pandemic demonstrated both the potential and limitations of mRNA-based vaccines. While very effective, current mRNA-LNP vaccines face challenges including significant reactogenicity, high dose requirements, and limited durability of immune responses. To address these shortcomings, many in the field are utilizing the unique ability of nucleic acid vaccines to express soluble mediators of adaptive immunity such as chemokines and cytokines as molecularly encoded adjuvants. While effective in preclinical models, cytokines as molecular therapies have struggled with notable toxicity and off target effects in human clinical trials. Here we propose an innovative solution which aims to enhance next-generation nucleic acid vaccines by investigating novel cell-intrinsic immunomodulators as molecular adjuvants. Our preliminary data supports this hypothesis, and the feasibility of this approach showing that self-amplifying RNA (saRNA) mediated co- expression of vaccine antigens with cell-intrinsic immunomodulator, from a single RNA molecule, results in enhanced neutralizing antibody potency and durability, and protection against viral challenge. We hypothesize that this will avoid the toxicities associated with molecularly encoded adjuvants such as cytokines, while improving the vaccine induced adaptive immune response at a significantly lower dose. The two specific aims of this proposal focus on assessing co-expression model antigens of SARS-CoV-2 Spike and Influenza A virus H5N1 Hemagglutinin with key molecules involved in DC licensing and trafficking (CD40, CD80, CCR7, and T- bet.), either (Aim 1) delivered as a LNP-saRNAantigen/imod on a single molecule or (Aim 2) co-formulated as LNP-(mRNAantigen+mRNAimod). Antibody potency, breadth, and durability will be assessed and will safety and reactogenicity. We believe that this proposal has the potential to revolutionize vaccinology through our innovative approach of harnessing cell intrinsic immunomodulators targeting DC function and development as molecular vaccine adjuvants. Our strategy aims to enhance vaccine performance while reducing doses and reactogenicity, potentially addressing key limitations of current mRNA vaccines. Success will lead to more effective and better-tolerated vaccines for emerging infectious diseases, and pandemic preparedness. Results will advance our understanding of molecular adjuvants and may establish a new platform for next-generation nucleic acid vaccines with broader applications in infectious disease prevention.