tIn this study we aimed to identify genes that are responsive to pertussis toxin (PTx) and might eventu-ally be used as biological markers in a testing strategy to detect residual PTx in vaccines. By microarrayanalysis we screened six human cell types (bronchial epithelial cell line BEAS-2B, fetal lung fibroblastcell line MRC-5, primary cardiac microvascular endothelial cells, primary pulmonary artery smooth mus-cle cells, hybrid cell line EA.Hy926 of umbilical vein endothelial cells and epithelial cell line A549 andimmature monocyte-derived dendritic cells) for differential gene expression induced by PTx. Imma-ture monocyte-derived dendritic cells (iMoDCs) were the only cells in which PTx induced significantdifferential expression of genes. Results were confirmed using different donors and further extendedby showing specificity for PTx in comparison to Escherichia coli lipopolysaccharide (LPS) and Bordetellapertussis lipo-oligosaccharide (LOS). Statistical analysis indicated 6 genes, namely IFNG, IL2, XCL1, CD69,CSF2 and CXCL10, as significantly upregulated by PTx which was also demonstrated at the protein levelfor genes encoding secreted proteins. IL-2 and IFN- gave the strongest response. The minimal PTx con-centrations that induced production of IL-2 and IFN- in iMoDCs were 12.5 and 25 IU/ml, respectively.High concentrations of LPS slightly induced IFN- but not IL-2, while LOS and detoxified pertussis toxindid not induce production of either cytokine. In conclusion, using microarray analysis we evaluated sixhuman cell lines/types for their responsiveness to PTx and found 6 PTx-responsive genes in iMoDCs ofwhich IL2 is the most promising candidate to be used as a biomarker for the detection of residual PTx.
