Project Description

Direct Peptide Reactivity Assay (DPRA)


The OECD 442C direct peptide reactivity assay (DPRA) investigates the molecular initiating event of the AOP for skin sensitisation – haptenation. Utilising HPLC, the potential for the reactivity of a test substance to cysteine and lysine peptides is detected. Depletion of these peptides via test substance reactivity is used to support the discrimination between skin sensitisers and non-sensitisers.

Gentronix have validated their DPRA protocols to demonstrate proficiency for the OECD guideline, and now conduct these routinely to GLP.

OECD GuidelineOECD 442C
Adverse Outcome Pathway Key EventNumber 1 – the molecular initiating event (MIE)
What it measuresPeptide reactivity; the depletion of cysteine and lysine
What is the relevance of that?Covalent binding of a substance to skin proteins is considered the first step in skin allergenicity
Incubation time22-24 hours
Can be conducted to GLP?Yes
Protocol performedEURL ECVAM DB-ALM Protocol No 154

DPRA OECD 442C Proficiency Data

Test Chemicalin vivo classificationReactivity ClassDPRA ClassificationClassification Correct?
DNCBSensitiser (extreme)HighSensitiser
OxazoloneSensitiser (extreme)HighSensitiser
FormaldehydeSensitiser (strong)ModerateSensitiser
Benzyliden acetoneSensitiser (moderate)HighSensitiser
FarnesalSensitiser (weak)ModerateSensitiser
2,3-butanedioneSensitiser (weak)HighSensitiser
6-methyl coumarinNon-sensitiserNo/MinimalNon-sensitiser
Lactic acidNon-sensitiserNo/MinimalNon-sensitiser
4-methoxy acetophenoneNon-sensitiserNo/MinimalNon-sensitiser

Predictive Toxicology, Expertly Delivered