High Reproducibility of ELISPOT Counts from Nine Different Laboratories

Area of Science:

• Immunology
• Biotechnology
• Clinical Diagnostics

Background:

• ELISPOT assays are crucial for immune monitoring, measuring antigen-specific T-cell responses.
• Variability in manual spot counting leads to inconsistent results across different laboratories.
• Subjectivity in setting spot size parameters hinders accurate and reproducible T-cell quantification.

Purpose of the Study:

• To evaluate the effectiveness of statistics-based, automated size-gating for harmonizing ELISPOT spot counts.
• To compare the reproducibility of automated counting versus subjective manual counting in multi-laboratory settings.
• To assess the impact of automated analysis on inter-laboratory variability in T-cell enumeration.

Main Methods:

• ELISPOT assays were performed using peripheral blood mononuclear cells (PBMCs) stimulated with HCMV pp65 antigen.
• Plates were counted in nine laboratories using ImmunoSpot® Analyzers with both manual (Basic Count™) and automated (SmartCount™) methods.
• SmartCount™ employed automated spot size auto-gating and intensity auto-thresholding for analysis.

Main Results:

• Automated counting with SmartCount™ reduced the average coefficient of variation (CV) between laboratories from 26.7% to 6.7%.
• SmartCount™ demonstrated superior reproducibility in quantifying T-cell responses compared to subjective manual counting.
• The automated method effectively minimized inter-observer and inter-laboratory variability.

Conclusions:

• Statistics-based automated counting (SmartCount™) harmonizes ELISPOT results across different laboratories.
• Automated ELISPOT analysis enhances the accuracy and reproducibility of immune monitoring.
• This approach offers a standardized method for T-cell enumeration in clinical and research settings.