Comparison of T Cell Receptor-Induced Proximal Signaling and Downstream Functions in Immortalized and Primary T Cells

Department of Microbiology, University of Iowa, Iowa City, Iowa, USA.
PLoS ONE (Impact Factor: 3.23). 02/2009; 4(5):e5430. DOI: 10.1371/journal.pone.0005430
Source: PubMed


Human T cells play an important role in pathogen clearance, but their aberrant activation is also linked to numerous diseases. T cells are activated by the concurrent induction of the T cell receptor (TCR) and one or more costimulatory receptors. The characterization of signaling pathways induced by TCR and/or costimulatory receptor activation is critical, since these pathways are excellent targets for novel therapies for human disease. Although studies using human T cell lines have provided substantial insight into these signaling pathways, no comprehensive, direct comparison of these cell lines to activated peripheral blood T cells (APBTs) has been performed to validate their usefulness as a model of primary T cells.
We used quantitative biochemical techniques to compare the activation of two widely used human T cell lines, Jurkat E6.1 and HuT78 T cells, to APBTs. We found that HuT78 cells were similar to APBTs in proximal TCR-mediated signaling events. In contrast, Jurkat E6.1 cells had significantly increased site-specific phosphorylation of Pyk2, PLCgamma1, Vav1, and Erk1/Erk2 and substantially more Ca2+ flux compared to HuT78 cells and APBTs. In part, these effects appear to be due to an overexpression of Itk in Jurkat E6.1 cells compared to HuT78 cells and APBTs. Both cell lines differ from APBTs in the expression and function of costimulatory receptors and in the range of cytokines and chemokines released upon TCR and costimulatory receptor activation.
Both Jurkat E6.1 and HuT78 T cells had distinct similarities and differences compared to APBTs. Both cell lines have advantages and disadvantages, which must be taken into account when choosing them as a model T cell line.

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    • "In this study we employed an integrated single cell localization, activation and dynamic analysis platform that not only allowed us to assess the activation profiles of primary T cells but also interaction of T cells with dendritic cells (DCs). Primary T cells have been known to depict differential signalling and downstream responses compared to immortalized T cell lines such as Jurkat cells[36]. Our results show distinct calcium signalling trends in unstimulated and calcium ionophore-stimulated cells. Significant heterogeneity in dynamic activation profiles was observed in both cell populations. "

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    • "Note, that all three murine T cell subsets in our study expressed the ectoenzyme Pc-1 that is involved in the degradation of ADPR and AMP [9], [22], however, this did not translate into the formation of significant protein to permit the degradation of measurable amounts of ADPR to AMP. Obviously, human Jurkat T cells may differ from murine T cells in many respects [49], a phenomenon well known in the literature [50]. "
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