Direct Peptide Reactivity Assay (DPRA)

The OECD 442C in chemico direct peptide reactivity assay (DPRA) examines the first molecular key event of haptenation within the adverse outcome pathway (AOP) of skin sensitisation. Through employing HPLC with UV detection, the depletion of synthetic heptapeptides, containing either lysine or cysteine, co-incubated with test articles can be quantified. 

At Cyprotex, we offer the OECD 442C validated assay to support the identification of skin sensitisation liabilities within test articles in conjunction with other skin sensitisation assays to provide a comprehensive assessment of the key events involved in skin sensitisation.

Assessment of skin sensitising potential using the reporter cell line, KeratinoSens™:

• KE1 molecular Initiating Event: Attain critical information regarding the haptenation of test articles
• Discriminate between Reactivity Classes: Characterise test articles as either no/minimal, low, moderate or high reactivity (table 1 & 2)
• Integrated Skin Sensitisation Testing Strategy: Perform DPRA in conjunction with other in vitro assays (KeratinoSens™ & U-SENS™) to assess the 3 key events of skin sensitisation.

_{1) OECD (2024), Test No. 442C: In Chemico Skin Sensitisation: Assays addressing the Adverse Outcome Pathway key event on covalent binding to proteins, OECD Guidelines for the Testing of Chemicals, Section 4, OECD Publishing, Paris, https://doi.org/10.1787/978926....}