Establishment of time-resolved fluorescence immunochromatographic method for Toxoplasma gondii detection

Abstract

Toxoplasma gondii (T. gondii) is a parasitic zoonosis that causes abortion or congenital diseases. The purpose of this study is to establish a immunochromatographic assay (ICA) method using time-resolved fluorescence microspheres (TRFM) for T. gondii quantitative detection in serum. Firstly, we activated the TRFM and then coupled with anti-T. gondii antibodies (mAb1) and anti-BSA-DNP antibodies to prepare the TRFM-mAb1 probes and TRFM-BSA-DNP probes. Then, we optimized the coupling pH, T line antibody concentration, probes usage and detection time. Finally, we established the T. gondii-TRFMICA method and assemble the T. gondii-TRFMICA kit, the standard curve, sensitivity, precision, specificity, clinical sensitivity and specificity were evaluated. Under the optimized conditions, the T. gondii-TRFMICA test was achieved within 20 min with the sensitivity 0.1 ng/mL. The recoveries were ranging from 100–110% with the intra-assay and inter-assay CV lower than 10%. The kits have detection specificity for positive serum of several common infectious diseases and some common serum components, and have high detection sensitivity and specificity in human and cat clinical samples. A TRFMICA kit for T. gondii quantitative detection was successfully prepared with high sensitivity, specificity, precision and clinical sensitivity and specificity. We recommend TRFMICA as a promising technique in the clinical diagnosis and monitoring of toxoplasmosis in human and animals.

Keywords

• toxoplasma gondii
• time-resolved fluorescence microsphere
• immunochromatographic assay
• zoonosis