Human Cell Line Activation Test (h-CLAT, OECD 442E)

The human Cell Line Activation Test (h-CLAT) is a cell-based assay that identifies skin sensitizers by examining changes in the expression of cell surface markers (CD54 and CD86) implicated in dendritic cell activation, the third key event of the skin sensitization AOP.  Following exposure of the THP-1 human monocyte cell line to the test substance, expression levels of CD54 and CD86 are quantified by flow cytometry and compared to controls.

The method has been reviewed by the European Union Reference Laboratory for alternatives to animal testing (EURL-ECVAM) and has been recommended as a useful tool in an integrated testing strategy for identification of skin sensitizers. Currently, the assay has an accepted OECD guideline (OECD 442E). IIVS offers this assay as part of an Integrated Testing Strategy for predicting skin sensitization.


  • Human Cell Line model
  • Cytotoxicity assessment included
  • Well-established assay that is predictive across many chemistries
  • Sophisticated analysis of protein expression via flow cytometry

Please contact IIVS for more information on the h-CLAT assay and how it may be suitable for your organization’s testing needs.