In Vitro Activation in Dendritic Cells (OECD 442E)

The third key event in the skin sensitization adverse outcome pathways relates to dendritic cell activation and refers to the absolute necessity for a sensitizing material to bind and activate local dendritic cells.

Using OECD procedure 442E, chemicals that have the ability to activate dendritic cells are rapidly evaluated with mixtures or formulations. When this test method is used in conjunction with the OECD procedure 442C DPRA and OECD procedure 442D KeratinoSens test methods, skin sensitization adverse outcome pathways are evaluated completely without animals from molecular initiation (DPRA) to key stage 3.

In vitro skin sensitization assays described in OECD procedure 442E test method, It includes three different test methods that address the activation of dendritic cells, the third important event of skin sensitization. The methods in the test guide are:

• Human cell line activation assay that measures expression of specific cell surface markers associated with dendritic cells maturation, namely CD86 and CD54, using flow cytometry
• U86 cell line activation assay measuring expression of the specific cell surface marker CD937
• Interleukin-8 reporter gene assay that measures changes in a cytokine related to activation of dendritic cells by measuring the induction of IL-8 mRNA

Briefly, skin sensitization is defined by the United Nations global harmonized chemical classification and labeling system as an allergic reaction following skin contact with the tested chemical.

The adverse outcome pathway leading to skin sensitization includes a number of important events. This test method considers the activation of dendritic cells. Skin sensitizers have been reported to induce expression of cell membrane markers (CD54 and CD86) associated with activation of dendritic cells. These surface molecules are typical dendritic cells activation markers that play a critical role in T-cell priming by dendritic cells, activating an immune response. Data generated by this test method are evaluated in the context of an integrated approach, ie in combination with other in vitro and chemical skin sensitization models.

Our organization also provides in vitro activation (OECD 442E) testing services in dendritic cells with its trained and expert staff and advanced technological equipment, among the numerous test, measurement, analysis and evaluation studies it provides for businesses in various sectors.