RESUMEN
Recent characterization of broadly neutralizing antibodies (bnAbs) against influenza virus identified the conserved hemagglutinin (HA) stem as a target for development of universal vaccines and therapeutics. Although several stem bnAbs are being evaluated in clinical trials, antibodies are generally unsuited for oral delivery. Guided by structural knowledge of the interactions and mechanism of anti-stem bnAb CR6261, we selected and optimized small molecules that mimic the bnAb functionality. Our lead compound neutralizes influenza A group 1 viruses by inhibiting HA-mediated fusion in vitro, protects mice against lethal and sublethal influenza challenge after oral administration, and effectively neutralizes virus infection in reconstituted three-dimensional cell culture of fully differentiated human bronchial epithelial cells. Cocrystal structures with H1 and H5 HAs reveal that the lead compound recapitulates the bnAb hotspot interactions.
Asunto(s)
Anticuerpos Neutralizantes/química , Materiales Biomiméticos/farmacología , Subtipo H1N1 del Virus de la Influenza A/efectos de los fármacos , Gripe Humana/prevención & control , Piperazinas/farmacología , Piridinas/farmacología , Tetrazoles/farmacología , Inhibidores de Proteínas Virales de Fusión/farmacología , Internalización del Virus/efectos de los fármacos , Administración Oral , Animales , Materiales Biomiméticos/administración & dosificación , Materiales Biomiméticos/farmacocinética , Bronquios/virología , Células Cultivadas , Perros , Glicoproteínas Hemaglutininas del Virus de la Influenza/genética , Glicoproteínas Hemaglutininas del Virus de la Influenza/metabolismo , Humanos , Células de Riñón Canino Madin Darby , Ratones , Piperazinas/administración & dosificación , Piperazinas/farmacocinética , Piridinas/administración & dosificación , Piridinas/farmacocinética , Mucosa Respiratoria/virología , Tetrazoles/administración & dosificación , Tetrazoles/farmacocinética , Inhibidores de Proteínas Virales de Fusión/administración & dosificación , Inhibidores de Proteínas Virales de Fusión/farmacocinéticaRESUMEN
Broadly neutralizing antibodies against highly variable pathogens have stimulated the design of vaccines and therapeutics. We report the use of diverse camelid single-domain antibodies to influenza virus hemagglutinin to generate multidomain antibodies with impressive breadth and potency. Multidomain antibody MD3606 protects mice against influenza A and B infection when administered intravenously or expressed locally from a recombinant adeno-associated virus vector. Crystal and single-particle electron microscopy structures of these antibodies with hemagglutinins from influenza A and B viruses reveal binding to highly conserved epitopes. Collectively, our findings demonstrate that multidomain antibodies targeting multiple epitopes exhibit enhanced virus cross-reactivity and potency. In combination with adeno-associated virus-mediated gene delivery, they may provide an effective strategy to prevent infection with influenza virus and other highly variable pathogens.
Asunto(s)
Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , Camélidos del Nuevo Mundo/inmunología , Glicoproteínas Hemaglutininas del Virus de la Influenza/inmunología , Virus de la Influenza A/inmunología , Virus de la Influenza B/inmunología , Vacunas contra la Influenza/inmunología , Infecciones por Orthomyxoviridae/prevención & control , Animales , Anticuerpos Neutralizantes/química , Anticuerpos Neutralizantes/ultraestructura , Anticuerpos Antivirales/química , Anticuerpos Antivirales/ultraestructura , Cristalografía por Rayos X , Perros , Femenino , Epítopos Inmunodominantes/química , Epítopos Inmunodominantes/genética , Epítopos Inmunodominantes/inmunología , Células de Riñón Canino Madin Darby , Ratones , Ratones Endogámicos BALB C , Pruebas de Neutralización , Biblioteca de Péptidos , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunología , Anticuerpos de Dominio ÚnicoRESUMEN
Influenza therapeutics with new targets and mechanisms of action are urgently needed to combat potential pandemics, emerging viruses, and constantly mutating strains in circulation. We report here on the design and structural characterization of potent peptidic inhibitors of influenza hemagglutinin. The peptide design was based on complementarity-determining region loops of human broadly neutralizing antibodies against the hemagglutinin (FI6v3 and CR9114). The optimized peptides exhibit nanomolar affinity and neutralization against influenza A group 1 viruses, including the 2009 H1N1 pandemic and avian H5N1 strains. The peptide inhibitors bind to the highly conserved stem epitope and block the low pH-induced conformational rearrangements associated with membrane fusion. These peptidic compounds and their advantageous biological properties should accelerate the development of new small molecule- and peptide-based therapeutics against influenza virus.
