Structure and Function Analysis of an Antibody Recognizing All Influenza A Subtypes.

Influenza virus remains a threat because of its ability to evade vaccine-induced immune responses due to antigenic drift. Here, we describe the isolation, evolution, and structure of a broad-spectrum human monoclonal antibody (mAb), MEDI8852, effectively reacting with all influenza A hemagglutinin (HA) subtypes. MEDI8852 uses the heavy-chain VH6-1 gene and has higher potency and breadth when compared to other anti-stem antibodies. MEDI8852 is effective in mice and ferrets with a therapeutic window superior to that of oseltamivir. Crystallographic analysis of Fab alone or in complex with H5 or H7 HA proteins reveals that MEDI8852 binds through a coordinated movement of CDRs to a highly conserved epitope encompassing a hydrophobic groove in the fusion domain and a large portion of the fusion peptide, distinguishing it from other structurally characterized cross-reactive antibodies. The unprecedented breadth and potency of neutralization by MEDI8852 support its development as immunotherapy for influenza virus-infected humans.

An engineered bispecific DNA-encoded IgG antibody protects against Pseudomonas aeruginosa in a pneumonia challenge model.

The impact of broad-spectrum antibiotics on antimicrobial resistance and disruption of the beneficial microbiome compels the urgent investigation of bacteria-specific approaches such as antibody-based strategies. Among these, DNA-delivered monoclonal antibodies (DMAbs), produced by muscle cells in vivo, potentially allow the prevention or treatment of bacterial infections circumventing some of the hurdles of protein IgG delivery. Here, we optimize DNA-delivered monoclonal antibodies consisting of two potent human IgG clones, including a non-natural bispecific IgG1 candidate, targeting Pseudomonas aeruginosa. The DNA-delivered monoclonal antibodies exhibit indistinguishable potency compared to bioprocessed IgG and protect against lethal pneumonia in mice. The DNA-delivered monoclonal antibodies decrease bacterial colonization of organs and exhibit enhanced adjunctive activity in combination with antibiotics. These studies support DNA-delivered monoclonal antibodies delivery as a potential strategy to augment the host immune response to prevent serious bacterial infections, and represent a significant advancement toward broader practical delivery of monoclonal antibody immunotherapeutics for additional infectious pathogens.DNA-delivered monoclonal antibodies (DMAbs) can be produced by muscle cells in vivo, potentially allowing prevention or treatment of infectious diseases. Here, the authors show that two DMAbs targeting Pseudomonas aeruginosa proteins confer protection against lethal pneumonia in mice.

DMAb inoculation of synthetic cross reactive antibodies protects against lethal influenza A and B infections.

Influenza virus remains a significant public health threat despite innovative vaccines and antiviral drugs. A major limitation to current vaccinations and therapies against influenza virus is pathogenic diversity generated by shift and drift. A simple, cost-effective passive immunization strategy via in vivo production of cross-protective antibody molecules may augment existing vaccines and antiviral drugs in seasonal and pandemic outbreaks. We engineered synthetic plasmid DNA to encode two novel and broadly cross-protective monoclonal antibodies targeting influenza A and B. We utilized enhanced in vivo delivery of these plasmid DNA-encoded monoclonal antibody (DMAb) constructs and show that this strategy induces robust levels of functional antibodies directed against influenza A and B viruses in mouse sera. Mice receiving a single inoculation with anti-influenza A DMAb survive lethal Group 1 H1 and Group 2 H3 influenza A challenges, while inoculation with anti-influenza B DMAb yields protection against lethal Victoria and Yamagata lineage influenza B morbidity and mortality. Furthermore, these two DMAbs can be delivered coordinately resulting in exceptionally broad protection against both influenza A and B. We demonstrate this protection is similar to that achieved by conventional protein antibody delivery. DMAbs warrant further investigation as a novel immune therapy platform with distinct advantages for sustained immunoprophylaxis against influenza.