Development of highly sensitive bioluminescent enzyme immunoassay with ultra-wide measurable range for thyroid-stimulating hormone using firefly luciferase

A bioluminescent enzyme immunoassay (BLEIA) of thyroid-stimulating hormone (TSH) using biotinylated firefly luciferase as a labelling enzyme for an an tibody was developed. This immunoassay, of which method was one step sandwi ch method, had high sensitivity and very wide measurable range. The detecti on. limit for TSH was found to be 0.0025 muU ml(-1) and the measurable rang e for TSH was 0.0025-200 muU ml(-1). The conjugate for this BLEIA was prepa red by binding the antibody to the end of cross-linking reagent and strepta vidin (SA)-biotinylated luciferase complex to the opposite end of the cross -linking reagent, respectively. The stability of the conjugate was excellen t. It showed 70% conjugate activity at the storage of a week at 37 degreesC and 100% at the storage of 6 months at 4 degreesC. (C) 2001 Elsevier Scien ce B.V. All rights reserved.