NAB-Sure™ Principle

NAB-Sure SARS-CoV-2 Neutralizing Antibody Assay is developed based on our patented SPEAR technology. SPEAR is an ultrasensitive immunoassay platform in which two specifically designed DNA-conjugated detection probes in proximity (e.g., brought by target molecules) can generate DNA signal molecules that can be quantified using qPCR.

NAB-Sure is a competitive immunoassay version of SPEAR. In NAB-Sure SARS-CoV-2 Neutralizing Antibody Assay, SARS-CoV-2 spike protein S1 subunit and ACE2 are conjugated to the SPEAR DNA probe A and B, respectively. In the case of non-neutralizing antibodies, those antibodies are less effective at preventing S1 from interacting with ACE2 proteins, retaining the proximity of the two DNA-conjugated probes for SPEAR reactions. In contrast, neutralizing antibodies blocks the interaction between S1 and ACE2 proteins, which delocalizes the proximity reaction and causes SPEAR signal reduction.