ABSTRACT
Allergy contact dermatitis is a type IV delayed type hypersensitivity that is induced by exogenous compounds and involves many cell types. Traditional animal testing uses guinea pigs or mice as a model. With progress of the adverse outcome pathway(AOP)on skin sensitization, a concept for development of alternative methods based on a molecular initiating event and key events is provided. Dendritic cell(DC)activation plays a key role in the AOP. Many alternative methods have been developed,with several methods validated and accepted as guidance for assays. This paper examines DC screening, characteristics of test parameters, and limitations and applicability of DC-derived methods. Progress on interactions between DCs and other cells, co-culture systems, and the human body-on-a-chip will also be introduced. Altogether,this paper will provide information for optimization of in vitro alternative methods for sensitization detection.
ABSTRACT
Objective To establish a detection method integrating DPRA ( direct peptide reactivity assay) with h?CLAT ( human cell line activation test) to screen the skin sensitization potency of chemicals and plant extracts. Methods 12 chemicals and 7 plant extracts were chosen as the test substances. Firstly, the test substances were incubated together with two different peptides ( cysteine and lysine) respectively for reaction for 24 h. The peptide consumptions were analyzed by HPLC. Simultaneously, THP?1 cells were cultured in vitro and then exposed to different concentrations of test sub?stances for 24 h to examine the cell viability, cell surface markers CD54 and CD86 were assessed by flow cytometry. The predicting results were compared further between DPRA and h?CLAT. Results 12 chemicals were distinguished correctly by DPRA classified as 2 non?sensitizers and 10 sensitizers. The results of DPRA were in accordance with h?CLAT. Predic?ting the sensitization potency of plant extracts by DPRA showed that 6 plant extracts were determined as suspected sensiti?zers except for green tea extract. But using the method of h?CLAT, 4 plant extracts were examined as suspected sensitizers except for green tea extract, herba portulacae extract and ginseng fruit extract. The coherence of DPRA and h?CLAT was 0?57. Conclusion This detection method integrating DPRA with h?CLAT can predict single compound accurately. As for complex compound, it can achieve preliminary prediction and need other integrating methods to make a further identifica?tion.