Optimizing Microneutralization and IFN-γ ELISPOT Assays to Evaluate Mpox Immunity.

Area of Science:

• Immunology
• Virology
• Vaccinology

Background:

• Current pox virus assays are time-consuming and may require specific antigens.
• There is a need for efficient methods to measure immune responses to mpox (monkeypox virus).

Purpose of the Study:

• To develop and validate robust assays for measuring mpox-specific neutralizing antibodies.
• To develop and validate robust assays for measuring mpox-specific T cell responses.

Main Methods:

• Focused Reduction Neutralization Test (FRNT) was optimized and compared to plaque reduction neutralization test (PRNT).
• Interferon-gamma (IFN-γ) ELISPOT assay was optimized using UV-inactivated mpox antigen.
• Assays were performed on samples from volunteers vaccinated with Modified Vaccinia Ankara-Bavarian Nordic (MVA-BN).

Main Results:

• The FRNT showed good agreement with PRNT (R² = 0.787).
• Post-vaccination sera showed significantly higher neutralizing antibody titers compared to pre-vaccination sera.
• The IFN-γ ELISPOT assay detected significantly higher T cell responses in post-vaccination samples.

Conclusions:

• A novel microneutralization test correlates well with PRNT for mpox antibodies.
• UV-inactivated mpox is suitable for ELISPOT assays to detect cross-reactive T cells.
• These developed assays are valuable tools for future mpox vaccine research.