Abstract

Pleural empyema is characterized by excessive fibrin deposition and impaired fibrinolysis, largely driven by elevated plasminogen activator inhibitor-1 (PAI-1), which suppresses tissue plasminogen activator (tPA) activity. Current fibrinolytic therapies show variable efficacy and are often limited by PAI-1 inhibition. This study aimed to protect fibrinolytic activity from PAI-1 inhibition of tPA using monoclonal antibodies (mAbs) targeting PAI-1. A fluorescence-based FITC–fibrin 96-well assay was optimized to quantitatively monitor fibrin degradation. Using this platform, the effects of two mAbs, MA-55F4C12 and MA-56A7C10, were evaluated in vitro and ex vivo. Both antibodies protected tPA activity and enhanced plasmin generation by interfering with distinct steps of the PAI-1 inhibitory mechanism, including blocking PAI-1 binding to tPA, preventing stable PAI-1–tPA complex formation, and promoting PAI-1 inactivation. Combination treatment of mAbs demonstrated greater protection of fibrinolytic activity compared to individual antibodies, particularly under inhibitory conditions present in pleural fluid. These findings support a mechanism-based therapeutic strategy targeting PAI-1 to enhance fibrinolysis and improve treatment outcomes in pleural empyema.

Date of publication

Spring 5-2026

Document Type

Thesis (Local Only Access)

Language

english

Persistent identifier

http://hdl.handle.net/10950/5072

Degree

MS in Biotechnology

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