Human Cell Line Activation Test (h-CLAT)

Chemicals can cause the immunological sensitization of skin tissue. Upon repeated exposure, it can lead to allergic reaction of the skin (Allergic Contact Dermatitis, ACD). Because of increasing social concern about animal welfare and the use of animals in testing, many alternative, non-animal tests have been proposed. Measuring phenotypic changes induced by sensitizers, such as markers on dendritic cells, is an important in vitro approach for evaluating skin sensitization potential.

Creative BioMart has internally validated the human cell line activation test (h-CLAT) procedure and is offering the h-CLAT as a Good-Laboratory-Practices-compliant assay. The h-CLAT addresses the third key event of the skin sensitization, Adverse Outcome Pathway (AOP), by measuring CD86 and CD54 expression during dendritic cell (DC) activation in human monocytic leukemia (THP-1) cells. The results are considered relevant for the assessment of the skin sensitization potential of test chemicals. The h-CLAT assay also generates concentration-response information that may contribute to the assessment of potency.

Assay workflow:

Prediction model:

• Cell viability: ≥ 50% by Propidium Iodide
• Positive criteria: CD86 RFI ≥ 150% and/or CD54 RFI ≥ 200%
• 2 of 3 independent data, at any dose, should exceed the positive criteria

The h-CLAT could positively predict not only extreme and strong sensitizers, but also moderate and weak sensitizers, though the detection rates of weak sensitizers and non-sensitizers were comparatively low. However, since skin sensitization involves the complex immune system, it is recommended to evaluate skin sensitization by a combination of methods which reflect various stages of the allergic reaction.

Reference:

1. Miyazawa et al. Phenotypic alterations and cytokine production in THP-1 cells in response to allergens.Toxicology in Vitro 2007 Apr;21(3):428-37