Fast Track Proposals will be accepted. Direct to Phase II will not be accepted. Number of anticipated awards: 2-4 Budget (total costs): Phase I: $300,000 for up to 1 year; Phase II: $2,000,000 for up to 3 years. Background A major focus of HIV vaccine research has been the development of immunogens that elicit broadly neutralizing antibody responses targeting the envelope protein (Env). While the field has predominantly focused on immunogen design and soluble antigens, the targeted and controlled delivery of antigens and optimal antigen-adjuvant formulations has not received much attention and is a gap in the HIV field that needs to be addressed. Lipid- and polymer-based nanoparticle platforms have been shown to induce HIV-specific antibody and cellular immune responses in animal studies. HIV immunogens delivered via particle-based modalities may elicit better and improved humoral and cellular immune responses. Specifically, multivalent/repetitive antigenic display on particle-based carriers may allow for higher avidity interactions and stimulate a diverse set of B cells. Consequently, such multivalent antigen display may mediate efficient engagement and activation of B cells, promoting stimulation of lower avidity cells from the germline antibody repertoire thereby enhancing affinity maturation resulting in superior antibody responses characterized by improved breadth, potency, and durability. Additionally, the ability of nanoparticles to target specific cells and release antigens in a controlled and sustained manner without the complications of viral vector toxicity and anti-vector immune responses makes nanoparticles a promising alternative to viral vectors. Altogether, for elicitation of potent, protective and durable immune responses, HIV immunogen design and particulate delivery of antigens should remain mutually inclusive and should converge for the development of HIV vaccine candidates capable of effectively inducing B/T-cell activation. Project Goal Tailored immunogens (such as Envs, monomers, native and/or native-like trimers, nucleic acids/RNA such as mRNAs, self-amplifying RNAs) combined with an effective multivalent antigenic display on nanoparticles for delivery may provide a strategy to promote strong and long-lived neutralizing antibody responses against HIV and direct affinity maturation toward HIV neutralizing antibodies. The primary goal of this SBIR is to solicit proposals that cover the following activities. Phase I activities may include, but are not limited to: • Engineering, fabricating nanoparticle platforms/systems and approaches (such as synthetic and/or self-assembling particles and/or conjugating technologies to attach antigen to nanoparticles and/or immunogens to adjuvants and/or encapsulating antigens) for delivering existing and/or novel HIV immunogens (such as Envs, monomers, native and/or native-like trimers, nucleic acids/mRNA/self-amplifying RNAs) that can enhance formulation codelivery, stability and scalability. • Augmenting HIV vaccine development by enhanced presentation, trafficking and targeting the antigen presentation for the induction of broad humoral and cellular immune responses. • Developing and evaluating particulate systems (such as synthetic and/or self-assembling and/or covalent chemical attachment and/or encapsulation/condensation of an antigen) that can facilitate co-delivery and/or co-formulation of HIV antigens (such as Envs, monomers, native and/or native-like trimers, nucleic acids/RNA) with adjuvants (such as existing, licensed, biosimilar novel adjuvants/TLR agonists). • Developing optimal parameters/conditions for incorporation of HIV antigen(s) in nanoparticulate formulation. • Assessing the effects of modulating particle size, shape, surface properties, composition and modulus/elastic properties of particulate delivery system components on immune responses. • Conducting pre-formulation/formulation studies on particulate antigen combinations to understand the interactions and compatibility of components (excipients, buffers, pH) and effect on antigen epitope integrity and its performance. Page 107 • Developing assays and test methods to analyze and characterize molecular properties of the particulate-antigen formulations through in vitro (biophysical, physicochemical, binding assays) and/or in vivo testing (small animal studies). • Developing assays to quantify encapsulation efficiency, immunogen release and expression. • Studying conditions for controlling particle size and size distribution, charge, composition, and aggregation. • Conducting mixing, compatibility, studies and short-term stability studies on antigen-adjuvanted formulations. • Evaluating particulated formulation technologies for fabrication and development of HIV vaccine development. • Testing for batch-to-batch reproducibility and consistency of particulate formulations for manufacturing, impact of changes in scale, size of the batches. • Conducting studies whether the particulated formulations can be subjected to sterile filtration and assessing the composition of components after sterilization. • Developing an efficient process for early stage/pre-clinical studies, which could be adapted to scale-up studies and which can subsequently lead to the production of clinical grade material in conformance with current good manufacturing practices (cGMP). • Evaluating the immunogenicity and effectiveness of particle-based HIV protein and nucleic acid/RNA vaccine candidates using different co-delivery strategies such as, but not limited to, co-administration, colocalization, encapsulation, surface adsorption of antigens (vs. soluble antigen) in animal models. • Investigating the influence of heterologous prime-boost vaccination strategies on targeting B cell activation and maturation. • Investigating the effects of route of immunization, dose, dosage form, and dose-sparing capacity of particulate formulations on the particle distribution and kinetics of immunogen immune response. Phase II activities may include, but are not limited to: • Developing lead nanoparticle antigen formulation into an efficient, stable and reproducible process. • Generating a pilot lot and/or scale-up studies based on optimized conditions that can subsequently lead to the production of clinical grade material in conformance with current Good Manufacturing Practices (cGMP). • Developing cGMP manufacturing processes for developing nanoparticle formulations. • Translating into in vitro studies to proof of concept studies in NHPs, as warranted. • Developing methods to evaluate compositional quality on critical components in nanoparticles, for example, but not limited to, quality, manufacturability and stability/degradation of lipids and related components. • Evaluating the performance, effectiveness, and toxicity of particulated HIV vaccine candidates vs. soluble antigen in small animal models. • Establishing quality assurance and quality control, methodology and development protocols for generation of HIV antigen-adjuvanted formulations for codelivery.