PROJECT SUMMARY A major limiting factor to the development of successful subunit vaccines against emerging pathogens is the lack of effective and safe immune adjuvants. Biomaterials immunoengineering is a nascent field that is generating promising avenues for the development of subunit vaccines against infectious diseases, cancers, and autoimmune disorders. Peptide based biomaterials are attractive dueto their biocompatibility, ability to fold into specific structures, ease of synthesis, and the rich chemistry with which the primary sequence can be manipulated to control the immunomodulatory properties. We are interested in the development of self- assembling peptide biomaterials for applications in vaccine development and immunotherapies. In the current project, we will develop novel self-assembling heterochiral peptide biomaterials that engage mechanisms of autophagy for applications in vaccine development against mosquito-borne flaviviruses such as West Nile (WNV). In aim 1, we will synthesize peptides with various patterns of chiral amino acids and investigate the assembly, morphology, structure, and bulk material properties such as viscoelasticity and proteolytic stability. In Aim 2, we will investigate how chirality-induced changes in the physicochemical properties of peptide biomaterials impact mechanisms of autophagy, adjuvant potency, and antibody responses using model antigens or peptide and protein antigens derived from WNV. We will deliver antigenic peptides or protein domains from viruses via covalent linkage or shear-thinned with peptide hydrogels and investigate antibody responses, affinity, and neutralization capacity. In aim 3, we will test protection from WNV challenge and neuroinvasion in mouse models and assess translational capacity of peptide biomaterials using Japanese encephalitis antigens for which inactivated human vaccines are available to serve as controls. Completion of the proposed work will integrate the fields of biomaterials, chemistry, immunology, and virology for the development of biomaterials-based immunization platforms against not only WNV, but also other emerging flaviviruses of public health importance.