SUMMARY
The goal of this proposal is to develop therapeutic antibodies for the treatment of multidrug resistant (MDR) P.
aeruginosa infections, with an emphasis on sepsis. With the rise in antimicrobial resistance around the world we
are running out of therapeutic options against MDR P. aeruginosa. Our laboratory has identified a potential
solution to address this problem: a therapeutic antibody cocktail that targets the lipopolysaccharide of P.
aeruginosa. One of the antibodies present in the cocktail (WVU-VDC-S3D4, or S3D4 for short) completely
protects mice against lethal sepsis, preventing bacterial dissemination and cytokine storm. This antibody is also
more potent than vaccination with a P. aeruginosa whole cell vaccine or passive immunization with serum from
whole cell vaccinated mice. Most interestingly, S3D4 is also capable of directly killing P. aeruginosa in vitro in
the absence of complement or immune cells. In this proposal, we will characterize the mechanism of action of
S3D4, formulate it in an LPS multivalent antibody cocktail, and evaluate efficacy against MDR P. aeruginosa. To
do this, we will evaluate host and bacterial factors involved in S3D4 function (Aims 1 and 2). We will then combine
it as cocktail with three additional antibodies that target the 6 LPS serogroups that cause 87% of P. aeruginosa
bloodstream infection. Efficacy in vitro and in vivo will be evaluated with MDR clinical isolates (Aim 3). We will
also evaluate efficacy against P. aeruginosa biofilms. We hypothesize that a multivalent anti-LPS cocktail of
antibodies, alone or in combination with standard of care antibiotics, will be efficacious for the prevention and
treatment of MDR P. aeruginosa sepsis. By the completion of these studies, we anticipate to elucidate the
mechanism of action of a novel class of antibodies that can directly kill P. aeruginosa in vitro, which will help with
the production of additional antibodies with similar functions against other MDR organisms. We will also produce
proof of concept data to support the generation antibody therapy against P. aeruginosa infections. Altogether,
this project will generate important knowledge to improve the lives of patients affected by this MDR bacterium.
