A highly-sensitive sandwich enzyme-linked immunosorbent assay (ELISA) was developed for detecting soluble interleukin 6 receptor (sIL-6R) in human serum, a biomarker for inflammation. The aim was to set up, develop, and validate an inexpensive method to measure sIL-6R.
MoAb anti-H IL-6R was used as coating and recombinant human IL-6 was added in a second step followed by detection, using PoAb anti-H IL6R biotine. The optimal concentrations of MoAb anti-H IL-6R and PoAb anti-H IL6R biotine for the ELISA were tested in serial dilutions and were 2 μg/ml MoAB anti-H IL-6R PBS and 0.3 μg/ml PoAb anti-H IL6R biotine HPE buffer.
Intra- and inter-assay CV range were 4.6%, and 8.8% respectively. The developed ELISA correlated well with a commercially available kit (R&D Systems, Spearman correlation 0.86; p<0.001). The costs of one ELISA plate was approximately €90 compared to the current list price of €560 for the commercial kit.
In summary, we have developed and validated an inexpensive sIL-6R ELISA.