Species-specific quantification of circulating ebolavirus burden using VP40-derived peptide variants

Area of Science:

• Virology
• Immunology
• Mass Spectrometry

Background:

• Six ebolavirus species exist, including human pathogens like Ebola virus (EBOV) and Sudan virus (SUDV).
• Accurate species identification and viral load quantification are crucial for effective Ebola virus disease (EVD) patient management.
• Existing diagnostic methods may require improvement for rapid and specific detection across diverse Ebolavirus species.

Purpose of the Study:

• To develop a novel assay for detecting and quantifying the Ebolavirus VP40 matrix protein.
• To create a method capable of differentiating between various Ebolavirus species for improved diagnostics.
• To establish a sensitive and specific assay for Ebolavirus detection applicable in decentralized settings.

Main Methods:

• Development of an immunoprecipitation-coupled mass spectrometry (IP-MS) assay targeting Ebolavirus VP40 antigen.
• Selection and antibody generation for two specific VP40 regions (peptide 8 and peptide 12) with conserved yet variable sequences across species.
• Application of the IP-MS assay to spiked human plasma, virus-like particles, and infected non-human primate plasma.

Main Results:

• The IP-MS assay successfully detected and quantified VP40 from EBOV, SUDV, and Bundibugyo virus (BDBV).
• Sequence variations between EBOV and SUDV resulted in significant affinity differences for the targeted peptides (2.6-fold for p8, 19-fold for p12).
• The assay differentiated four of six known Ebolavirus species using a combination of peptide data, with limits of detection comparable to current surveillance methods.

Conclusions:

• The developed IP-MS assay provides a sensitive and specific method for Ebolavirus VP40 detection and species differentiation.
• The assay's ability to distinguish between lethal Ebolavirus species holds significant potential for improved clinical diagnostics and patient care.
• The use of a miniature mass spectrometry instrument enhances the assay's feasibility for use in decentralized laboratories, broadening its applicability in outbreak surveillance.