A biodegradable nano-microparticle prime-boost vaccine strategy

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DESCRIPTION (provided by applicant): Biodegradable nano- and microparticle technologies may offer safe, synergistic approaches for the multi-mode presentation of a vaccine antigen to the human immune system in a single formulation. Our proposal harnesses (1) the ability of virus-like nanoparticles to achieve a strong priming immune response, (2) the efficiency of biodegradable microparticles as slow-release "natural" boosting platforms, and (3) the capability of co-delivery of immunostimulatory agonists into a single platform for the development of the next generation of malaria transmission-blocking vaccines (TBVs). TBVs are considered one of the critical tools in the global effort to eliminate and eradicate malaria, since they function to block mosquito transmission of both drug- resistant and susceptible parasites from one individual to another. However, TBVs suffer from the lack of natural boosting, as the target antigens themselves are only present inside the mosquito, and the recent mathematical models for implementation suggest that the ideal vaccine development goal is a single immunization approach that is capable of eliciting high titer antibodies for over at least one year, but preferably more. To circumvent these TBV as well as general vaccine development concerns, we propose to engineer a "mixed mode" nano-/microparticle delivery system that leverages different attributes of lymph node (LN)- targeting biodegradable nanoparticles for effective presentation of the TBV antigen, AnAPN1, to dendritic cells (DC) and biodegradable microparticles for sustained release of AnAPN1 antigen to permit continued boosting, therefore inducing a superior immune response in the vaccinated individual. For our initial studies in a rodent model, we will develop size-controlled biodegradable LN-targeting nanoparticles for effective delivery and presentation of the AnAPN1 antigen to LN-resident DCs, followed by functional characterization of the AnAPN1-specific immune response. We will then engineer DC-activating nanoparticles to potentiate the antibody response to co-delivered AnAPN1 antigen followed by characterization of the effect of nanoparticle- delivered adjuvant on the functional AnAPN1-specific immune response. Lastly, we will construct a single-dose vaccine with DC-targeting biodegradable nanoparticles and AnAPN1-releasing microparticles and assess the durability and transmission-blocking efficacy of AnAPN1-specific antibodies in a large animal model.