# The quantitative detection method employing a combination of high-affinity antibodies targeting PCT

## TL;DR

This study develops high-affinity antibodies and a new detection method for procalcitonin, a marker of inflammation, with potential clinical applications.

## Contribution

A novel fluorescent microsphere-based immunochromatographic strip (FM-ICS) for PCT detection with high sensitivity and optimized antibody pairs.

## Key findings

- Generated 83 monoclonal antibodies against PCT, with 15 high-affinity IgG1 antibodies selected.
- FM-ICS achieved a detection limit of 1.5 ng/mL and showed robust clinical performance.
- The method offers potential for monitoring infections and guiding antibiotic use in sepsis.

## Abstract

Procalcitonin (PCT) is a widely recognized inflammation marker utilized in various clinical testing contexts and is subject to ongoing refinements, thereby imposing greater demands on core antibodies. However, the published literature lacks a comprehensive description of them.

In this study, we initially expressed the full-length PCT protein in eukaryotic systems, followed by conventional antibody engineering techniques for in vitro cell fusion and the selection of positive hybridoma cell clones specific to the PCT protein.

A total of 83 positive clones were generated, among which 15 high-affinity IgG1 subtype monoclonal antibodies were selected for complementarity-determining region (CDR) analysis to predict potential antigen-recognition epitopes. We provided a detailed characterization of the binding properties between these high-affinity antibodies and the PCT protein. Utilizing time-resolved fluorescent microsphere (TRFM), a novel fluorescent microsphere-based immunochromatographic strip (FM-ICS) approach was developed, with MomAb-8 serving as the capture antibody and MomAb-20 functioning as the labeling antibody. Ultimately, following the preliminary evaluation of clinical samples, it was demonstrated that this FM-ICS exhibited a favorable linear range, stability, and clinical relevance.

This study presents a novel approach to enhancing the efficiency of antibody screening across a diverse array of combinations. Furthermore, the method established herein holds significant potential for clinical application in detecting PCT protein using FM-ICS.

•High-Affinity Antibody Generation: Developed 83 monoclonal antibodies against procalcitonin (PCT), selecting 15 high-affinity IgG1 antibodies.•Novel Detection Method: Created a fluorescent microsphere immunochromatographic strip (FM-ICS) for PCT detection with excellent sensitivity.•Clinical Sensitivity: FM-ICS demonstrated a detection limit of 1.5 ng/mL and robust performance in clinical sample testing.•Optimization: Structural analysis and affinity testing improved antibody pair combinations for enhanced detection.•Application: The method offers potential for infection monitoring and guiding antibiotic use, particularly in sepsis.

High-Affinity Antibody Generation: Developed 83 monoclonal antibodies against procalcitonin (PCT), selecting 15 high-affinity IgG1 antibodies.

Novel Detection Method: Created a fluorescent microsphere immunochromatographic strip (FM-ICS) for PCT detection with excellent sensitivity.

Clinical Sensitivity: FM-ICS demonstrated a detection limit of 1.5 ng/mL and robust performance in clinical sample testing.

Optimization: Structural analysis and affinity testing improved antibody pair combinations for enhanced detection.

Application: The method offers potential for infection monitoring and guiding antibiotic use, particularly in sepsis.