Development of Human Monoclonal Antibody Therapeutic against Klebsiella pneumoniae Infection

he greatest danger after hemorrhage in combat related injuries is sepsis. Despite the reduction in post-traumatic sepsis over the past 20 years, mortality may be as high as 25%. K. pneumoniae is a gram negative organism and leading cause of sepsis. Infections with this organism often result in incomplete wound healing. Importantly the worldwide emergence of antibiotic-resistant strains of K.p. has become a cause for concern with extended-spectrum beta-lactamase and carbapenemase-producing strains emerging with increasing frequency. Multi-drug resistance has left military clinicians with few or no treatment options. Because of the threat of drug resistance, wound infections caused by K.p. will not be resolved with currently available antibiotics; therefore, alternative treatment strategies are urgently needed. Monoclonal antibodies are non-traditional treatment modalities that have been FDA approved for use in a variety of viral (e.g. Ebola, rabies, RSV) and bacterial (e.g. Clostridium sp. Bacillus anthracis) infections. These antibodies can be used as an adjunct to antibiotics and can be administered prophylactically or therapeutically. The advantages of human monoclonal antibody therapy include prolonged presence in serum and tissue, inherent pathogen specificity without affecting normal bacterial flora, and potentiation of sustained bacterial killing. The mechanisms of antibody inactivation of gram negative bacteria include direct binding to cell walls, neutralization of secreted toxins and virulence factors, complement deposition, and opsonization by neutrophils and macrophages. Sustained inactivation of gram negative bacteria and their virulence factors by multiple mechanisms reduces septic shock and aids in the prevention of emerging resistance. CentiVax provides a technology platform to quickly generate a repertoire of therapeutic antibodies capable of inactivating drug-resistant K.p. found in traumatic wounds. We will select antibody combinations which when combined as a therapeutic cocktail, will act synergistically providing military and civilian physicians an alternative approach to controlling bacterial sepsis and shock. CentiVax has formed CRADAs with the Navy Medical Research Center (NMRC) and Walter Reed Army Institute for Research (WRAIR), and is currently producing panels of high affinity, thermostable monoclonal antibodies to common wound pathogens for therapeutic treatment of sepsis caused by Staphylococcus and Pseudomonas sp. Our primary objective in this Phase I SBIR is to develop human monoclonal antibodies which will inhibit the growth and virulence of Klebsiella pneumoniae in both biofilm and planktonic states. We will focus on five bacterial targets: fimbriae types I & III, outer membrane proteins OMPA & OMPK36, and one siderophore receptor Fep A. From this group we will generate more than 100 monoclonal antibodies (and antibody sequences) which will be evaluated for binding affinity.