A novel assay for quantifying Gn-LRP1-mediated neutralizing antibodies against severe fever with thrombocytopenia syndrome virus.

Accurate and efficient determination of neutralizing antibody (nAb) is critical for assessing individual immune status of severe fever with thrombocytopenia syndrome (SFTS) and identifying key ecological reservoirs of the SFTS virus (SFTSV). However, conventional virus neutralization tests (cVNT) require live virus and are limited by their inability to support rapid, high-throughput screening. Here, we report a novel SFTSV virus neutralization test targeting the interaction between the SFTSV Gn protein and its receptor (LRP1). The test, which has been validated with SFTS patient plasma, achieves a sensitivity of 96.79% and a specificity of 100%. It also shows good correlation with cVNT, with an R² value of 0.8902 in head-to-head comparison. This platform offers a safe, rapid, and high-throughput alternative for large-scale population screening and the real-time monitoring of immune responses in SFTS patients.