PROJECT SUMMARY There have been tremendous recent advances in our understanding of the pathogenesis of otitis media (OM) due to nontypeable Haemophilus influenzae (NTHI). Significantly, we’ve come to appreciate the role that biofilms play in both post-tympanostomy tube otorrhea as well as in the chronicity and recurrence of NTHI- induced OM. Bacteria dwelling within a biofilm present a formidable obstacle to effectors of immunity and antibiotic therapies. Thereby, in order to design novel and effective strategies to better treat and/or prevent otorrhea and OM, it is necessary to understand both the biology of biofilms, including their unique biochemical and proteomic composition, as well as how one might undermine these structures to mediate a therapeutic ‘cure’. Through the successful conduct of a series of three highly integrated Specific Aims, we will expand upon a solid foundation of a growing body of literature from our laboratories which show that we can target a family of bacterial DNA-binding proteins (IHF and HU) that are critical to stabilize extracellular DNA (eDNA) present within an NTHI biofilm to reduce or eradicate that structure both in vitro and in vivo. Here, we will now identify and characterize the best therapeutic antigenic targets within both IHF and HU, with a focus on specific functional domains. We will also determine both the kinetics of release and the availability of IHF and HU subunits within the NTHI eDNA-DNABII dependent extracellular matrix in order to identify an optimal therapeutic window for intervention. Moreover, we will determine the therapeutic value of using biofilm-focused, epitope-targeted monoclonal antibodies and cocktails thereof to resolve biofilms associated with chronic otorrhea and otitis media. These latter studies will first be conducted in vitro using both monospecies biofilms, as well as those of mixed otopathogen etiology, to better reflect the clinical condition. Finally, we will determine the relative therapeutic efficacy of this approach in vivo, using a chinchilla model of experimental OM. The chinchilla represents an anatomically appropriate, robust, reproducible and extensively studied animal model of this highly prevalent pediatric biofilm disease in which to conduct these essential pre-clinical studies. Importantly, whereas our primary target for disease intervention is OM, because NTHI causes many biofilm-associated diseases of the human respiratory tract, the studies proposed here will also likely provide a basis for the design of better practices to treat disease in other parts of the airway such as the sinuses (chronic rhinosinusitis), the tonsils and adenoids (tonsillitis, adenoiditis), the bronchus (chronic cough and bronchitis) and the lung (COPD, early stage CF, community acquired pneumonia). Our Specific Aims are perfectly aligned with both Healthy People 2020 (Hearing and Other Sensory or Communication Disorders, ENT-VSL-2: “Reduce otitis media in children and adolescents”), ...