Abstract
The Pig-a assay is being developed as an in vivo gene mutation assay for regulatory safety assessments. The assay is based on detecting mutation in the endogenous Pig-a gene of treated rats by using flow cytometry to measure changes in cell surface markers of peripheral blood cells. Here we present a methodology for demonstrating that phenotypically mutant rat T-cells identified by flow cytometry contain mutations in the Pig-a gene, an important step for validating the assay. In our approach, the mutant phenotype T-cells are sorted into individual wells of 96-well plates and expanded into clones. Subsequent sequencing of genomic DNA from the expanded clones confirms that the Pig-a assay detects exactly what it claims to detect—cells with mutations in the endogenous Pig-a gene. In addition, determining the spectra of Pig-a mutations provides information for better understanding the mutational mechanism of compounds of interest. Our methodology of combining phenotypic antibody labeling, magnetic enrichment, sorting, and single-cell clonal expansion can be used in genotoxicity/mutagenicity studies and in other general immunotoxicology research requiring identification, isolation, and expansion of extremely rare subpopulations of T-cells.
This chapter reflects the views of the authors and should not be construed to represent FDA’s views or policies.
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Dobrovolsky, V.N., Revollo, J., Petibone, D.M., Heflich, R.H. (2017). In Vivo Rat T-Lymphocyte Pig-a Assay: Detection and Expansion of Cells Deficient in the GPI-Anchored CD48 Surface Marker for Analysis of Mutation in the Endogenous Pig-a Gene. In: Gautier, JC. (eds) Drug Safety Evaluation. Methods in Molecular Biology, vol 1641. Humana Press, New York, NY. https://doi.org/10.1007/978-1-4939-7172-5_7
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DOI: https://doi.org/10.1007/978-1-4939-7172-5_7
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