Establishment of an in vitro photoallergy test using NCTC2544 cells and IL-18 production

Abstract

Differentiation between photoallergenic and phototoxic reactions induced by low molecular weight compounds represents a current problem. The use of keratinocytes as a potential tool for the detection of photoallergens as opposed to photoirritants is considered an interesting strategy for developing in vitro methods. We have previously demonstrated the possibility to use the human keratinocyte cell line NCTC2455 and the production of interleukin-18 (IL-18) to screen low molecular weight sensitizers. The purpose of this work was to explore the possibility to use the NCTC2544 assay to identify photoallergens and discriminate from phototoxic chemicals.First, we identified suitable condition of UV-irradiation (3.5 J/cm 2 ) by investigating the effect of UVAirradiation on intracellular IL-18 on untreated or chloropromazine (a representative phototoxic compound)-treated NCTC2544 cells. Then, the effect of UVA-irradiation over NCTC2544 cells treated with increasing concentrations of 15 compounds including photoallergens (benzophenone, 4-ter-butyl-4-methoxydibenzoylmethane, 2-ethylexyl-p-methoxycinnamate, ketoprofen, 6-methylcumarin); photoirritant and photoallergen (4-aminobenzoic acid, chlorpromazine, promethazine); photoirritants (acridine, ibuprofen, 8-methoxypsoralen, retinoic acid); and negative compounds (lactic acid, SDS and p-phenilendiamine) was investigated. Twenty-four hours after exposure, cytotoxicity was evaluated by the MTT assay or LDH leakage, while ELISA was used to measure the production of IL-18. At the maximal concentration assayed with non-cytotoxic effects (CV80 under irradiated condition), all tested photoallergens induced a significant and a dose-dependent increase of intracellular IL-18 following UVA irratiation, whereas photoirritants failed.We suggest that this system may be useful for the in vitro evaluation of the photoallergic potential of chemicals.

Pilot Study Of Photoallergic Reactions To Non-steroidal Anti-inflammatory Agents, Chemicals Used In Dental Composites And Antiseptic Agents Among Dental Professionals

“…Application in dentistry is available as well. It was considered to be photoirritant (28) and photosensitizer (29).…”

Photoprotection in changing times – UV filter efficacy and safety, sensitization processes and regulatory aspects

“…IL-1a or IL-18) and different adhesion and growth factors upon contact with sensitizers and photosensitizers [381,382]. This is the basis of a whole series of proposed alternative methods, for example the cell-based AREn32 or NCTC 2544 IL-18 assays and the SenCeeTox, or SENS-IS assays [383][384][385][386][387][388][389]. With SENS-IS, for which human 3D reconstructed epidermis (EpiSkin) is used, a quantification of 62 biomarkers, which are split into three groups (irritation, ARE and SENS-IS), is possible [390].…”

Establishment of an in vitro photoassay using THP-1 cells and IL-8 to discriminate photoirritants from photoallergens

“…In a recent workshop (Ceridono et al, 2012), it was underlined that the waveband concerned is mainly UVA, with some drugs extending to UVB and others to visible. Thus, we have chosen a pure UVA lamp source with an irradiance spectra ranging from 320 nm to 400 nm with a peak at 365 nm similarly to other studies (Galbiati et al, 2013). The use of this irradiation source can underestimate the impact of some light visible photoreactive compounds.…”

“…Regarding photosensitization only few works have been published mainly based on DC-like cells (Hoya et al, 2009;Karschuk et al, 2010), and more recently a promising keratinocyte photoassay has been proposed (Galbiati et al, 2013 Recently, we have proposed THP-1 and the release of the chemokine IL-8, along with p38 MAPK activation as a model for screening sensitizers (Mitjans et al, 2008;Mitjans et al, 2010). Based on the assumption that contact photosensitization has the same mechanistic of contact sensitization, the purpose of this work was to explore the suitability of this model to discriminate photosensitizers from photoirritants.…”