Comparison of T cell receptor-induced proximal signaling and downstream functions in immortalized and primary T cells.
BACKGROUND
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.


RESULTS
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.


CONCLUSIONS
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.
Department of Microbiology, University of Iowa, Iowa City, Iowa, USA.
Rebekah R
RR
Bartelt
Noemi
N
Cruz-Orcutt
Michaela
M
Collins
Jon C D
JC
Houtman
D020013:Calcium Signaling; D002460:Cell Line; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D051418:Focal Adhesion Kinase 2 / Q000378:metabolism; D006801:Humans; D019169:Jurkat Cells; D008213:Lymphocyte Activation; D018448:Models, Immunological; D051966:Phospholipase C gamma / Q000378:metabolism; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D051567:Proto-Oncogene Proteins c-vav / Q000378:metabolism; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism*
D016207:Cytokines; D051567:Proto-Oncogene Proteins c-vav; D011948:Receptors, Antigen, T-Cell; C496618:VAV1 protein, human; D011505:Protein-Tyrosine Kinases; D051418:Focal Adhesion Kinase 2; C080813:emt protein-tyrosine kinase; D048049:Extracellular Signal-Regulated MAP Kinases; D051966:Phospholipase C gamma