Measurement of ligand-induced activation in single viable T cells using the lacZ reporter gene

J. Karttunen, N. Shastri

Research output: Contribution to journalArticlepeer-review

151 Scopus citations


We have used the bacterial β-galactosidase gene (lacZ) as a reporter gene for the rapid measurement of T-cell antigen receptor (TCR)-mediated activation of individual T cells. The reporter construct contained the lacZ gene under the control of the nuclear factor of activated T cells (NF-AT) element of the human interleukin 2 enhancer [Fiering, S., Northrop, J. P., Nolan, G. P., Matilla, P., Crabtree, G. R. and Herzenberg, L. A. (1990) Genes Dev. 4, 1823-1834]. The activity of the intracellular lacZ enzyme was analyzed by flow cytometric measurement of fluorescein accumulation in cells loaded with the fluorogenic β-galactosidase substrate fluorescein di-β-D-galactopyranoside. As a model system, the T-cell hybridoma BO4H9.1, which is specific for the lysozyme peptide (amino acids 74-88)/Ab complex, was transfected with the NF-AT-lacZ construct. lacZ activity was induced in 50-100% of the transfectant cells following exposure to pharmacological agents, to the physiological peptide/major histocompatibility complex ligand, or to other TCR-specific stimuli. Interestingly, increasing concentrations of the stimulus increased the fraction of lacZ+ cells, but not the level of lacZ activity per cell. Even under widely varying levels of stimulus, the level of lacZ activity in individual lacZ+ cells remained within a remarkably narrow range. These results demonstrate that TCR-mediated activation can be readily measured in single T cells and strongly suggest that, once committed to activation, the level of NF-AT transcriptional activity in individual T cells is independent of the form or concentration of stimulus. This assay is likely to prove useful for the study of early activation events in individual T cells and of TCR ligands.

Original languageEnglish (US)
Pages (from-to)3972-3976
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number9
StatePublished - 1991
Externally publishedYes


  • T-cell activation
  • flow cytometry
  • superantigens
  • β-galactosidase

ASJC Scopus subject areas

  • General


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