Quantum dot fluorescent microsphere-based immunochromatographic strip for detecting PRRSV antibodies

Area of Science:

• Veterinary Virology
• Immunodiagnostics
• Nanotechnology in diagnostics

Background:

• Porcine Reproductive and Respiratory Syndrome (PRRS) is a significant swine disease caused by PRRSV, with current vaccines offering inadequate protection.
• Existing diagnostic methods for PRRSV antibodies lack sufficient speed, sensitivity, or cross-protection, necessitating improved serological approaches.
• The development of precise, sensitive, simple, and rapid diagnostic tools is crucial for effective PRRSV management.

Purpose of the Study:

• To develop and evaluate a novel immunochromatography strip (ICS) utilizing quantum dot fluorescent microspheres (QDFM) for the detection of PRRSV antibodies.
• To assess the sensitivity, specificity, and stability of the developed QDFM ICS for PRRSV antibody detection.

Main Methods:

• Development of QDFM tracers covalently linked to the PRRSV N protein.
• Coating of monoclonal antibodies against PRRSV N and M proteins on nitrocellulose membranes as control (C) and test (T) lines.
• Evaluation of QDFM ICS performance using specificity and sensitivity assays, and comparison with commercial ELISA kits on 189 clinical samples.

Main Results:

• The QDFM ICS detected PRRSV antibodies in under 10 minutes with high sensitivity and specificity.
• The minimum detection limit was 1.2 ng/mL at a 1:2,048 dilution, comparable to ELISA kits, with no cross-reactivity observed.
• Analysis of 189 clinical samples showed QDFM ICS sensitivity, specificity, and accuracy of 96.7%, 97.9%, and 97.4%, respectively.
• The test strips demonstrated good storage stability for up to 6 months at 4°C and 4 months at room temperature.

Conclusions:

• QDFM ICS is a viable novel method for both on-site and in-lab detection of PRRSV antibodies.
• The developed QDFM ICS exhibits performance characteristics (sensitivity, specificity, accuracy) on par with commercial ELISA kits.
• This rapid, sensitive, and specific diagnostic tool holds significant potential for on-site PRRSV screening, aiding the swine industry in managing this evolving viral threat.