High-throughput antibody-based assays to identify and quantify radiation-responsive protein biomarkers.

PURPOSE

After a radiological 'dirty bomb' incident in a major metropolitan center, substantial numbers of people may be exposed to radiation. However, only a fraction of those individuals will need urgent medical attention. Consequently, a rapid screening test is needed to identify those people who require immediate treatment.

MATERIAL AND METHODS

Ten normal human cell lines were screened by enzyme-linked immunosorbent assay (ELISA) for the expression of a dozen secreted cytokines that have been reported to have changes in protein or mRNA levels at 1, 2, and 3 days after 0-10 Gy irradiation using (137)Cs gamma rays at 0.82 Gy min(-1). After this systematic in vitro screen, we measured changes in the level of a subset of these candidate proteins in plasma from irradiated C57BL/6 mice (n = 3 per group), comparing shams with a single radiation dose (5 Gy X-rays) at 3.7 Gy min(-1) at 6 h after irradiation.

RESULTS

We identified four cytokine molecules that had altered levels after radiation exposure, one of which, Interleukin (IL) 6, was consistently elevated after irradiation in vitro and in vivo.

CONCLUSIONS

Our findings underscore the potential for IL6 as a marker for an immunoassay-based, rapid, high-throughput biodosimeter.