# EPY001, a Novel Monoclonal Antibody Against Pseudomonas aeruginosa Targeting OprF

## TL;DR

This paper describes a new monoclonal antibody, EPY001, targeting a key protein in Pseudomonas aeruginosa, but finds it insufficient to protect against lethal infection in mice.

## Contribution

EPY001 is a novel monoclonal antibody against OprF in P. aeruginosa, developed using proteoliposome-based immunization.

## Key findings

- EPY001 binds strongly to OprF with nanomolar affinity.
- Targeting OprF alone does not protect mice from lethal P. aeruginosa infection.
- Functional assays reveal OprF's role in biofilm formation and antibiotic resistance.

## Abstract

Pseudomonas aeruginosa (P. aeruginosa) is a high-priority opportunistic pathogen responsible for severe healthcare-associated infections exhibiting multidrug resistance, emphasizing the urgent need for alternative therapeutic strategies. Monoclonal antibodies (mAbs) targeting the highly conserved outer membrane protein OprF represent a promising approach to mitigate its infectivity. OprF, the major and highly conserved outer membrane protein of P. aeruginosa, plays key roles in the pathogenesis of this bacterium, including biofilm formation, host cell adhesion, immune sensing, and resistance to macrophage clearance, making it a crucial factor in virulence and a promising immunotherapeutic target. Here, we report the preclinical evaluation of EPY001, an anti-OprF mAb generated by immunization of a macaque with OprF-containing proteoliposomes. EPY001 exhibited strong nanomolar binding to OprF. Epitope mapping suggests recognition of a conformational epitope, underscoring the value of proteoliposome-based immunization for membrane protein targets. Functional assays provide insights into OprF’s role in biofilm formation, pyocyanin production, and antibiotic resistance. However, in vivo studies revealed that targeting OprF alone is insufficient to protect mice from lethal infection. These findings contribute to ongoing efforts to develop effective alternatives to conventional antibiotics against this resilient pathogen.