The GARD assay for potency assessment of skin sensitizing chemicals

Kathrin S. Zeller, Andy Forreryd, Tim Lindberg, Ann-Sofie Albrekt, Aakash Chawade, Malin Lindstedt Dept. of Immunotechnology, Lund University, Lund, Sweden; Swedish University of Agricultural Sciences, Alnarp, Sweden Summary The GARD assay is a cell-based transcriptional biomarker assay for the prediction of chemical  ensitizers1 targeting key event 3, dendritic cell activation, of the skin sensitization AOP. […]

Kathrin S. Zeller, Andy Forreryd, Tim Lindberg, Ann-Sofie Albrekt, Aakash Chawade, Malin Lindstedt
Dept. of Immunotechnology, Lund University, Lund, Sweden; Swedish University of Agricultural Sciences, Alnarp, Sweden

Summary
The GARD assay is a cell-based transcriptional biomarker assay for the prediction of chemical  ensitizers1 targeting key event 3, dendritic cell activation, of the skin sensitization AOP. Here, we present a modified assay based on Random Forest modelling, which is capable of predicting CLP
potency classes (1A – strong sensitizers, 1B – weak sensitizers, no category – non-sensitizers) as described by the European CLP regulation with an accuracy of 75 % (no cat), 75 % (1B) and 88 % (1A) based on a test set consisting of 18 chemicals previously unseen to the model.
We further can link the activation of distinct pathways to the chemical protein reactivity, showing that our transcriptomic approach can reveal information contributing to the understanding of underlying mechanisms in sensitization.

Results and Discussion
We here present a potency prediction approach based on a Random Forest model and 18 transcripts. 18 chemicals previously unseen to the model were classified as shown in Tables 1, 4 and Fig. 1. Interestingly, diethyl maleate, misclassified as 1A instead of 1B, is a human potency class 2 according to4, and iodopropynyl butylcarbamate, wrongly predicted as 1B instead of 1A, is classified as human potency class 44. Thus, the model seems to show more agreement with human data than CLP classifications (mainly derived from animal data) based on this limited dataset. Also Fig. 1C supports the hypothesis, that both data and model contain information allowing the prediction of human potency.
Furthermore, Key Pathway Advisor analysis reveals that these data can be used to investigate the cellular response in more detail (Table 3). In conclusion, we show that the modified GARD assay is capable of providing potency information, which is imperative for quantitative risk assessment of chemical sensitizers.

The GARD assay for potency assessment of skin sensitizing chemicals_ESTIV 2016_Zeller_p

GARD – The story

Olivia Larne, Andy Forreryd, Ann Sofie Albrekt, Carl Arne Krister Borrebaeck, Henrik Johansson, Malin Lindstedt SenzaGen, Sweden, Lund, Department of Immunotechnology, Lund University, Sweden, Lund   Background To prevent the general population for unnecessary exposure to sensitizing substances, the substances have to be safety tested. Regulatory authorities and economic interests request animal free methodology. Genomic […]

Olivia Larne, Andy Forreryd, Ann Sofie Albrekt, Carl Arne Krister Borrebaeck, Henrik Johansson, Malin Lindstedt
SenzaGen, Sweden, Lund, Department of Immunotechnology, Lund University, Sweden, Lund

 

Background

To prevent the general population for unnecessary exposure to sensitizing substances, the substances have to be safety tested. Regulatory authorities and economic interests request animal free methodology. Genomic Allergen Rapid Detection, GARD, is an in vitro test developed for the prediction of sensitizing chemicals. It is based on differential expression of disease-associated genomic biomarkers in a human myeloid dendritic cell line.
Here, we describe the development of the GARD platform and its downstream innovations.

Poster:
GARD – The Story_ESTIV 2016

GARD – the future of sensitization testing and safety assessment of chemicals using a genomic-based platform

BACKGROUND Genomic Allergen Rapid Detection, GARD, is an in vitro test developed for the prediction of sensitizing chemicals. It is based on differential expression of disease-associated genomic biomarkers in a human myeloid dendritic cell line. Here, we describe the development, scientific validation, applications and the current state of the GARD platform. The scientific rationale behind […]

BACKGROUND
Genomic Allergen Rapid Detection, GARD, is an in vitro test developed for the prediction of sensitizing chemicals. It is based on differential expression of disease-associated genomic biomarkers in a human myeloid dendritic cell line.
Here, we describe the development, scientific validation, applications and the current state of the GARD platform. The scientific rationale behind the use of genomic biomarker signatures are detailed, linked to the AOP in a biological context, and to advantages realized through multivariate computational prediction models in a technological context.

RESUME
The GARD assay is elastic, it can be used for several applications. Today, two are developed:

GARDskin
– Hazard identification of skin sensitizers
– Accuracy: ~90%
– Initiated ECVAM validation (OECD TGP no. 4.106)

GARDair
– Hazard identification of respiratory sensitizers
– Accuracy: ~85%

GARD–the future of sensitization testing and safety assessment of chemicals, using a genomics-based platform_Eurotox 2016_p

GARD–the future of sensitization testing and safety assessment of chemicals, using a genomics-based platform

Henrik Johansson, Andy Forreryd, Olivia Larne, Ann Sofie Albrekt, Carl Arne Krister Borrebaeck, Malin Lindstedt SenzaGen, Sweden, Lund, Department of Immunotechnology, Lund University, Sweden, Lund   Background Genomic Allergen Rapid Detection, GARD, is an in vitro test developed for the prediction of sensitizing chemicals. It is based on differential expression of disease-associated genomic biomarkers in […]

Henrik Johansson, Andy Forreryd, Olivia Larne, Ann Sofie Albrekt, Carl Arne Krister Borrebaeck, Malin Lindstedt
SenzaGen, Sweden, Lund, Department of Immunotechnology, Lund University, Sweden, Lund

 

Background
Genomic Allergen Rapid Detection, GARD, is an in vitro test developed for the prediction of sensitizing chemicals. It is based on differential expression of disease-associated genomic biomarkers in a human myeloid dendritic cell line.

Here, we describe the development, scientific validation, applications and the current state of the GARD platform. The scientific rationale behind the use of genomic biomarker signatures are detailed, linked to the AOP in a biological context, and to advantages realized through multivariate computational prediction models in a technological context.

Resume
GARDskin
– Hazard identification of skin sensitizers
– Accuracy: ~90%
– Initiated ECVAM validation (OECD TGP no. 4.106)
GARDair
– Hazard identification of respiratory sensitizers
– Accuracy: ~85%

Poster:
GARD–the future of sensitization testing and safety assessment of chemicals, using a genomics-based platform

Signature biomarker analysis for prediction of skin sensitizers using a cell-based in vitro alternative to animal experimentation

Henrik Johansson, Ann-Sofie Albrekt, Carl A.K. Borrebaeck, Malin Lindstedt Department of Immunotechnology, Lund University, BMC D13, 21184 Lund, Sweden Introduction Allergic contact dermatitis is an inflammatory skin disease caused by immunological responses towards chemical haptens. Current test of sensitizing chemicals rely on animal experimentation. New legislations on the registration and use of chemicals within pharmaceutical […]

Henrik Johansson, Ann-Sofie Albrekt, Carl A.K. Borrebaeck, Malin Lindstedt
Department of Immunotechnology, Lund University, BMC D13, 21184 Lund, Sweden

Introduction
Allergic contact dermatitis is an inflammatory skin disease caused by immunological responses towards chemical haptens. Current test of sensitizing chemicals rely on animal experimentation. New legislations on the registration and use of chemicals within pharmaceutical and cosmetic industries have stimulated significant research efforts to develop alternative, human cell-based assays for the prediction of sensitization.
We have developed a novel cell-based assay for the prediction of sensitizing chemicals, based on differentially regulated transcripts in the myeloid cell-line MUTZ-3.

 

Conclusions
We have identified a biomarker signature with accurate predictive power, which represents a compelling readout for an in vitro assay useful for the identification of human sensitizing chemicals. The biomarker signature include transcripts involved in relevant biological pathways, such as oxidative stress and xenobiotoic induced responses, which sheds light on the molecular interactions involved in the process of sensitization.

Poster:

Signature biomarker analysis for prediction of skin sensitizers using a cell-based in vitro alternative to animal experimentation_EAACI 2011 LTH_p