This contract supports the identification of human B cell epitopes derived from three viral pathogens; Zika, Marburg and Venezuelan equine encephalitis viruses, combined with basic studies to understand protective immunity mediated by antibodies. Milestones include 1) epitope identification; 2) epitope validation that must include in vitro evaluation using human samples; 3) submission of epitope data, computer software, and structural data to the Immune Epitope Database and Analysis Resource; and 4) studies to help understand the mechanisms of protection or pathogenesis elicited by antibodies associated with the newly identified epitopes. The Contractor will discover and characterize B cell epitopes on the Envelope (Env) proteins of Zika virus (ZIKV prM/E), Marburg virus (MARV GP), and Venezuelan equine encephalitis virus (VEEV E1/E2). They will generate new monoclonal antibodies (MAbs) by B cell cloning and next-generation sequencing using human clinical samples from both naturally infected and vaccinated individuals; Map the binding site of each Mab; Validate the functional relevance of each epitope to neutralize or, in the case of ZIKV MAbs, to enhance infectivity; and determine the mechanism of action of each Mab. Rapid mapping of specific antibodies using integral molecular' s high throughput epitope mapping platform (arrays of cells expressing S protein with point mutations at every amino acid position).