Detecting specific cytotoxic T lymphocytes against SARS-coronavirus with DimerX HLA-A2:Ig fusion protein

Area of Science:

• Immunology
• Virology
• Flow Cytometry

Background:

• Severe acute respiratory syndrome (SARS)-coronavirus infection elicits an immune response.
• Understanding the role of cytotoxic T lymphocytes (CTLs) in viral clearance is crucial.
• Developing rapid assays to detect virus-specific immune cells is essential for public health.

Purpose of the Study:

• To assess specific cytotoxic T lymphocytes (CTLs) against SARS-CoV using a modified DimerX flow cytometry assay.
• To evaluate the kinetics of CTL response post-SARS infection.
• To determine the correlation between flow cytometry and ELISPOT assays for CTL detection.

Main Methods:

• Peripheral blood mononuclear cells (PBMC) were collected from HLA-A2+ SARS-recovered donors.
• A modified DimerX flow cytometry assay was employed to detect CD8+DimerX-S1203+ CTLs.
• Enzyme-linked immune absorbent spot (ELISPOT) assay was used for comparison, detecting interferon-gamma positive spots.

Main Results:

• Specific CD8+DimerX-S1203+ CTLs were detected in PBMCs up to 3 months post-recovery from SARS.
• The percentage of detected CTLs correlated with the number of interferon-gamma spots in ELISPOT assays.
• The DimerX assay demonstrated sensitivity in detecting virus-specific T cell responses.

Conclusions:

• Modified DimerX flow cytometry is a viable real-time method for screening CTLs against SARS-CoV.
• This assay can be adapted for detecting CTLs against epitopes from newly identified viruses.
• The findings support the utility of flow cytometry in immunological surveillance of viral infections.