Fever is a systemic inflammatory response of the body to pyrogens. Nuclear factor κB (NF-κB) is a central signalling molecule that causes the excessive secretion of various proinflammatory factors induced by pyrogens. This study explored the feasibility of a novel reporter gene assay (RGA) for pyrogen detection using RAW 264.7 cells stably transfected with the NF-κB reporter gene as a pyrogenic marker. Pyrogen was incubated with the transgenic cells, and the intensity of the fluorescence signal generated by luciferase secreted by the reporter gene was used to reflect the degree of activation of NF-κB, so as to quantitatively detect the pyrogens. The RGA could detect different types of pyrogens, including the lipopolysaccharide (LPS) of gram-negative bacteria, the lipoteichoic acid (LTA) of gram-positive bacteria, and the zymosan of fungi, and a good dose-effect relationship was observed in terms of NF-κB activity. The limits of detection of the RGA to those pyrogens were 0.03 EU/ml, 0.001 μg/ml, and 1 μg/ml, respectively. The method had good precision and accuracy and could be applied to many biological products (e.g., nivolumab, rituximab, bevacizumab, etanercept, basiliximab, haemophilus influenzae type b conjugate vaccine, 23-valent pneumococcal polysaccharide vaccine, and group A and group C meningococcal conjugate vaccine). The results of this study suggest that the novel RGA has a wide pyrogen detection spectrum and is sufficiently sensitive, stable, and accurate for various applications.

A novel reporter gene assay for pyrogen detection