Preliminary findings of an in vitro assay based on human complement activation for the detection of chemicals with phototoxicity potential

By Sladowski, D. - Steer, S. - Moore, L. - Glassborow, R. - Clothier, R. - Balls, M.

Eight known photosensitising chemicals and one non-photosensitiser were compared for their ability to activate the complement system of human serum in both the presence and the absence of ultraviolet (UV) radiation. Commercially available ELISA systems for the detection of C4d and iC3b fragments were used to investigate the classical and alternative pathways, respectively. The results indicated that, whereas the classical pathway was unaffected, all the photosensitisers tested were capable of activating the alternative pathway in the presence of UV light, and that this activation occurred at different levels, depending upon the chemical itself. The non-photosensitising chemical, sodium dodecyl sulphate, acted as a negative control. It is, therefore, suggested that this type of method could be considered for inclusion in any battery of in vitro tests designed for the detection of potential photosensitising chemicals.