Advancing Toxoplasma gondii multiplex serology

Area of Science:

• Immunology
• Infectious Diseases
• Public Health

Background:

• Toxoplasma gondii is a prevalent zoonotic pathogen with significant public health implications.
• Current understanding of long-term consequences, risk factors, and co-infections related to T. gondii remains limited.
• Large-scale seroepidemiological studies are essential for addressing these knowledge gaps but require robust diagnostic tools.

Purpose of the Study:

• To significantly advance a previously developed multiplex serology assay for T. gondii.
• To improve assay characteristics for high-throughput, large-scale seroprevalence studies.
• To enable reliable detection of T. gondii antibodies under diverse assay conditions.

Main Methods:

• Development of truncated versions of immunodominant antigens (SAG1D1 and P22trunc) for enhanced assay performance.
• Evaluation of assay performance using magnetic and non-magnetic beads at various sample dilutions (1:100 and 1:1,000).
• Comparison with the gold-standard Sabin-Feldman dye test and derivation of seropositivity thresholds using finite mixture models and ROC analysis.

Main Results:

• The improved assay using SAG1D1 and P22trunc demonstrated significantly enhanced signal-to-noise ratios and near-perfect concordance with the Sabin-Feldman dye test.
• High diagnostic accuracy was achieved at 1:100 dilution (Sensitivity: 98% for SAG1D1, 94% for P22trunc; Specificity: 93% for SAG1D1, 95% for P22trunc).
• Reproducible performance metrics were confirmed at 1:1,000 dilution with both magnetic and non-magnetic beads.

Conclusions:

• The revised multiplex serology assay provides robust and reproducible T. gondii antibody measurements across various conditions.
• This advancement facilitates the inclusion of T. gondii detection in multi-pathogen multiplex serology panels for large-scale research.
• The improved assay is a valuable tool for enhancing insights into T. gondii epidemiology, risk factors, and public health impact.